Enzyme Nomenclature

EC 2.1.1 (continued)

Methyltransferases

Continued from EC 2.1.1.1 to EC 2.1.1.50

See separate file for EC 2.1.1.101 to EC 2.1.1.150, EC 2.1.1.151 to EC 2.1.1.200, EC 2.1.1.201 to EC 2.1.1.250, EC 2.1.1.251 to EC 2.1.1.300 and EC 2.1.1.301 to EC 2.1.1.362.

Contents

EC 2.1.1.51 transferred now covered by EC 2.1.1.187 and EC 2.1.1.188
EC 2.1.1.52 transferred now EC 2.1.1.171, EC 2.1.1.172, EC 2.1.1.173 and EC 2.1.1.142
EC 2.1.1.53 putrescine N-methyltransferase
EC 2.1.1.54 deoxycytidylate C-methyltransferase
EC 2.1.1.55 tRNA (adenine-N6-)-methyltransferase
EC 2.1.1.56 mRNA (guanine-N7-)-methyltransferase
EC 2.1.1.57 methyltransferase cap1
EC 2.1.1.58 deleted, included in EC 2.1.1.57
EC 2.1.1.59 [cytochrome c]-lysine N-methyltransferase
EC 2.1.1.60 calmodulin-lysine N-methyltransferase
EC 2.1.1.61 tRNA (5-methylaminomethyl-2-thiouridylate)-methyltransferase
EC 2.1.1.62 mRNA (2'-O-methyladenosine-N6-)-methyltransferase
EC 2.1.1.63 methylated-DNA—[protein]-cysteine S-methyltransferase
EC 2.1.1.64 3-demethylubiquinone-9 3-O-methyltransferase
EC 2.1.1.65 licodione 2'-O-methyltransferase
EC 2.1.1.66 deleted now covered by EC 2.1.1.230
EC 2.1.1.67 thiopurine S-methyltransferase
EC 2.1.1.68 caffeate O-methyltransferase
EC 2.1.1.69 5-hydroxyfuranocoumarin 5-O-methyltransferase
EC 2.1.1.70 8-hydroxyfuranocoumarin 8-O-methyltransferase
EC 2.1.1.71 phosphatidyl-N-methylethanolamine N-methyltransferase
EC 2.1.1.72 site-specific DNA-methyltransferase (adenine-specific)
EC 2.1.1.73 deleted
EC 2.1.1.74 methylenetetrahydrofolate—tRNA-(uracil54-C5)-methyltransferase (FADH2-oxidizing)
EC 2.1.1.75 apigenin 4'-O-methyltransferase
EC 2.1.1.76 quercetin 3-O-methyltransferase
EC 2.1.1.77 protein-L-isoaspartate(D-aspartate) O-methyltransferase
EC 2.1.1.78 isoorientin 3'-O-methyltransferase
EC 2.1.1.79 cyclopropane-fatty-acyl-phospholipid synthase
EC 2.1.1.80 protein-glutamate O-methyltransferase
EC 2.1.1.81 deleted, included in EC 2.1.1.49
EC 2.1.1.82 3-methylquercetin 7-O-methyltransferase
EC 2.1.1.83 3,7-dimethylquercetin 4'-O-methyltransferase
EC 2.1.1.84 methylquercetagetin 6-O-methyltransferase
EC 2.1.1.85 protein-histidine N-methyltransferase
EC 2.1.1.86 tetrahydromethanopterin S-methyltransferase
EC 2.1.1.87 pyridine N-methyltransferase
EC 2.1.1.88 8-hydroxyquercetin 8-O-methyltransferase
EC 2.1.1.89 tetrahydrocolumbamine 2-O-methyltransferase
EC 2.1.1.90 methanol—corrinoid protein Co-methyltransferase
EC 2.1.1.91 isobutyraldoxime O-methyltransferase
EC 2.1.1.92 deleted, now EC 2.1.1.69
EC 2.1.1.93 deleted, identical to EC 2.1.1.70
EC 2.1.1.94 tabersonine 16-O-methyltransferase
EC 2.1.1.95 tocopherol C-methyltransferase
EC 2.1.1.96 thioether S-methyltransferase
EC 2.1.1.97 3-hydroxyanthranilate 4-C-methyltransferase
EC 2.1.1.98 diphthine synthase
EC 2.1.1.99 3-hydroxy-16-methoxy-2,3-dihydrotabersonine N-methyltransferase
EC 2.1.1.100 protein-S-isoprenylcysteine O-methyltransferase

See the following files for:

EC 2.1.1.101 to EC 2.1.1.150
EC 2.1.1.151 to EC 2.1.1.200
EC 2.1.1.201 to EC 2.1.1.250
EC 2.1.1.251 to EC 2.1.1.300
EC 2.1.1.301 to EC 2.1.1.362

Entries

[EC 2.1.1.51 Transferred entry: rRNA (guanine-N1-)-methyltransferase. Now covered by EC 2.1.1.187 [23S rRNA (guanine745-N1)-methyltransferase] and EC 2.1.1.188 [23S rRNA (guanine748-N1)-methyltransferase]. (EC 2.1.1.51 created 1976, deleted 2010)]

[EC 2.1.1.52 Transferred entry: rRNA (guanine-N2)-methyltransferase. Now covered by EC 2.1.1.171 [16S rRNA (guanine966-N2)-methyltransferase], EC 2.1.1.172 [16S rRNA (guanine1207-N2)-methyltransferase], EC 2.1.1.173 [23S rRNA (guanine2445-N2)-methyltransferase] and EC 2.1.1.174 [23S rRNA (guanine1835-N2)-methyltransferase] (EC 2.1.1.52 created 1976, deleted 2010)]

EC 2.1.1.53

Accepted name: putrescine N-methyltransferase

Reaction: S-adenosyl-L-methionine + putrescine = S-adenosyl-L-homocysteine + N-methylputrescine

For diagram of reaction, click here.

Other name(s): putrescine methyltransferase

Systematic name: S-adenosyl-L-methionine:putrescine N-methyltransferase

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 9075-39-2

References:

1. Mizusaki, S., Tanabe, Y., Noguchi, M. and Tamaki, E. Phytochemical studies on tobacco alkaloids. XIV. The occurence and properties of putrescine N-methyltransferase in tobacco roots. Plant Cell Physiol. 12 (1971) 633-640.

[EC 2.1.1.53 created 1976]

EC 2.1.1.54

Accepted name: deoxycytidylate C-methyltransferase

Reaction: 5,10-methylenetetrahydrofolate + dCMP = dihydrofolate + deoxy-5-methylcytidylate

Other name(s): deoxycytidylate methyltransferase; dCMP methyltransferase

Systematic name: 5,10-methylenetetrahydrofolate:dCMP C-methyltransferase

Comments: dCMP is methylated by formaldehyde in the presence of tetrahydrofolate. CMP, dCTP and CTP can act as acceptors, but more slowly.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 61970-01-2

References:

1. Kuo, T.-T. and Tu, J. Enzymatic synthesis of deoxy-5-methyl-cytidylic acid replacing deoxycytidylic acid in Xanthomonas oryzae phage Xp12DNA. Nature 263 (1976) 615. [PMID: 980110]

[EC 2.1.1.54 created 1978]

EC 2.1.1.55

Accepted name: tRNA (adenine-N6-)-methyltransferase

Reaction: S-adenosyl-L-methionine + tRNA = S-adenosyl-L-homocysteine + tRNA containing N6-methyladenine

Systematic name: S-adenosyl-L-methionine:tRNA (adenine-N6-)-methyltransferase

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 9014-53-3

References:

1. Mandel, R., Hacker, B. and Maag, T.A. Altered transfer RNA methylase patterns in Marek's disease tumors. Cancer Res. 31 (1971) 613-616. [PMID: 4996578]

2. Mittelman, A., Hall, R.H., Yohn, D.S. and Grace, J.T. The in vitro soluble RNA methylase activity of SV40-induced hamster tumors. Cancer Res. 27 (1967) 1409-1414. [PMID: 4292682]

3. Sharma, O.K. Differences in the transfer RNA methyltransferases from normal rat liver and Novikoff hepatoma. Biochim. Biophys. Acta 299 (1973) 415-427. [PMID: 4349332]

[EC 2.1.1.55 created 1981]

EC 2.1.1.56

Accepted name: mRNA (guanine-N7-)-methyltransferase

Reaction: S-adenosyl-L-methionine + a 5′-(5′-triphosphoguanosine)-[mRNA] = S-adenosyl-L-homocysteine + a 5′-(N7-methyl 5′-triphosphoguanosine)-[mRNA]

Glossary: a 5′-(5′-triphosphoguanosine)-[mRNA] = G5′ppp5’R-[mRNA]
a 5′-(N7-methyl 5′-triphosphoguanosine)-[mRNA] = m7G5′ppp5’R-[mRNA] = cap0

Other name(s): messenger ribonucleate guanine 7-methyltransferase; guanine-7-methyltransferase; messenger RNA guanine 7-methyltransferase; S-adenosyl-L-methionine:mRNA (guanine-7-N)-methyltransferase

Systematic name: S-adenosyl-L-methionine:mRNA (guanine-N7-)-methyltransferase

Comments: The nucleoside next to the terminal guanosine may be either guanosine or adenosine.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 56941-25-4

References:

1. Ensinger, M.J., Martin, S.A., Paoletti, E. and Moss, B. Modification of the 5'-terminus of mRNA by soluble guanylyl and methyl transferases from vaccinia virus. Proc. Natl. Acad. Sci. USA 72 (1975) 2525-2529. [PMID: 1058472]

2. Groner, Y., Gilbao, E. and Aviv, H. Methylation and capping of RNA polymerase II primary transcripts by HeLa nuclear homogenates. Biochemistry 17 (1978) 977-982. [PMID: 629955]

3. Martin, S.A. and Moss, B. Modification of RNA by mRNA guanylyltransferase and mRNA (guanine-7)methyltransferase from vaccinia virions. J. Biol. Chem. 250 (1975) 9330-9335. [PMID: 1194287]

4. Martin, S.A., Paoletti, E. and Moss, B. Purification of mRNA guanylyltransferase and mRNA (guanine-7-) methyltransferase from vaccinia virions. J. Biol. Chem. 250 (1975) 9322-9329. [PMID: 1194286]

[EC 2.1.1.56 created 1981]

EC 2.1.1.57

Accepted name: methyltransferase cap1

Reaction: S-adenosyl-L-methionine + a 5'-(N7-methyl 5'-triphosphoguanosine)-(purine-ribonucleotide)-[mRNA] = S-adenosyl-L-homocysteine + a 5'-(N7-methyl 5'-triphosphoguanosine)-(2'-O-methyl-purine-ribonucleotide)-[mRNA]

Other name(s): messenger ribonucleate nucleoside 2'-methyltransferase; messenger RNA (nucleoside-2'-)-methyltransferase; MTR1; cap1-MTase; mRNA (nucleoside-2'-O)-methyltransferase (ambiguous); S-adenosyl-L-methionine:mRNA (nucleoside-2'-O)-methyltransferase

Systematic name: S-adenosyl-L-methionine:5-(N7-methyl 5-triphosphoguanosine)-(purine-ribonucleotide)-[mRNA] 2-O-methyltransferase

Comments: This enzyme catalyses the methylation of the ribose on the first transcribed nucleotide of mRNA or snRNA molecules, which may be either guanosine or adenosine. This methylation event is known as cap1, and occurrs in all mRNAs and snRNAs of higher eukaryotes, including insects, vertebrates and their viruses. The human enzyme can also methylate mRNA molecules that lack methylation on the capping 5'-triphosphoguanosine [6].

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 61970-02-3

References:

1. Barbosa, E. and Moss, B. mRNA(nucleoside-2'-)-methyltransferase from vaccinia virus. Purification and physical properties. J. Biol. Chem. 253 (1978) 7692-7697. [PMID: 701281]

2. Barbosa, E. and Moss, B. mRNA(nucleoside-2'-)-methyltransferase from vaccinia virus. Characteristics and substrate specificity. J. Biol. Chem. 253 (1978) 7698-7702. [PMID: 701282]

3. Boone, R.F., Ensinger, M.J. and Moss, B. Synthesis of mRNA guanylyltransferase and mRNA methyltransferases in cells infected with vaccinia virus. J. Virol. 21 (1977) 475-483. [PMID: 833934]

4. Ensinger, M.J., Martin, S.A., Paoletti, E. and Moss, B. Modification of the 5'-terminus of mRNA by soluble guanylyl and methyl transferases from vaccinia virus. Proc. Natl. Acad. Sci. USA 72 (1975) 2525-2529. [PMID: 1058472]

5. Groner, Y., Gilbao, E. and Aviv, H. Methylation and capping of RNA polymerase II primary transcripts by HeLa nuclear homogenates. Biochemistry 17 (1978) 977-982. [PMID: 629955]

6. Werner, M., Purta, E., Kaminska, K.H., Cymerman, I.A., Campbell, D.A., Mittra, B., Zamudio, J.R., Sturm, N.R., Jaworski, J. and Bujnicki, J.M. 2'-O-ribose methylation of cap2 in human: function and evolution in a horizontally mobile family. Nucleic Acids Res. 39 (2011) 4756-4768. [PMID: 21310715]

[EC 2.1.1.57 created 1981 (EC 2.1.1.58 created 1981, incorporated 1984), modified 2014]

[EC 2.1.1.58 Deleted entry: mRNA (adenosine-2'-O-)-methyltransferase. Now included with EC 2.1.1.57 mRNA (nucleoside-2'-O-)-methyltransferase. (EC 2.1.1.58 created 1981, deleted 1984)]

EC 2.1.1.59

Accepted name: [cytochrome c]-lysine N-methyltransferase

Reaction: S-adenosyl-L-methionine + [cytochrome c]-L-lysine = S-adenosyl-L-homocysteine + [cytochrome c]-N6-methyl-L-lysine

Other name(s): cytochrome c (lysine) methyltransferase; cytochrome c methyltransferase; cytochrome c-specific protein methylase III; cytochrome c-specific protein-lysine methyltransferase

Systematic name: S-adenosyl-L-methionine:[cytochrome c]-L-lysine N6-methyltransferase

Comments: One of a group of enzymes methylating proteins; see also EC 2.1.1.43 histone-lysine N-methyltransferase and EC 2.1.1.60 calmodulin-lysine N-methyltransferase.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 82047-78-7

References:

1. Durban, E., Nochumson, S., Kim, S. and Paik, W.K. Cytochrome c-specific protein-lysine methyltransferase from Neurospora crassa. Purification, characterization, and substrate requirements. J. Biol. Chem. 253 (1978) 1427-1435. [PMID: 203592]

2. Nochumson, S., Durban, E., Sangduk, K. and Paik, W.K. Cytochrome c-specific protein methylase III from Neurospora crassa. Biochem. J. 165 (1977) 11-18. [PMID: 196592]

3. Valentine, J. and Pettigrew, G.W. A cytochrome c methyltransferase from Crithidia oncopelti. Biochem. J. 201 (1982) 329-338. [PMID: 6282265]

[EC 2.1.1.59 created 1982, modified 1983]

EC 2.1.1.60

Accepted name: calmodulin-lysine N-methyltransferase

Reaction: S-adenosyl-L-methionine + calmodulin L-lysine = S-adenosyl-L-homocysteine + calmodulin N6-methyl-L-lysine

Other name(s): S-adenosylmethionine:calmodulin (lysine) N-methyltransferase

Systematic name: S-adenosyl-L-methionine:calmodulin-L-lysine N6-methyltransferase

Comments: One of a group of enzymes methylating proteins; see also EC 2.1.1.43 histone-lysine N-methyltransferase and EC 2.1.1.59 [cytochrome-c]-lysine N-methyltransferase.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 75603-20-2

References:

1. Sitaramayya, A., Wright, L.S. and Siegel, F.L. Enzymatic methylation of calmodulin in rat brain cytosol. J. Biol. Chem. 255 (1980) 8894-8900. [PMID: 6773954]

[EC 2.1.1.60 created 1982, modified 1983]

EC 2.1.1.61

Accepted name: tRNA (5-methylaminomethyl-2-thiouridylate)-methyltransferase

Reaction: S-adenosyl-L-methionine + tRNA containing 5-aminomethyl-2-thiouridine = S-adenosyl-L-homocysteine + tRNA containing 5-methylaminomethyl-2-thiouridylate

Other name(s): transfer ribonucleate 5-methylaminomethyl-2-thiouridylate 5-methyltransferase; tRNA 5-methylaminomethyl-2-thiouridylate 5'-methyltransferase

Systematic name: S-adenosyl-L-methionine:tRNA (5-methylaminomethyl-2-thio-uridylate)-methyltransferase

Comments: This enzyme is specific for the terminal methyl group of 5-methylaminomethyl-2-thiouridylate.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 39391-17-8

References:

1. Taya, Y. and Nishimura, S. Biosynthesis of 5-methylaminomethyl-2-thiouridylate. I. Isolation of a new tRNA-methylase specific for 5-methylaminomethyl-2-thiouridylate. Biochem. Biophys. Res. Commun. 51 (1973) 1062-1068. [PMID: 4703553]

2. Taya, Y. and Nishimura, S. In: Salvatore, F., Borek, E., Zappia, V., Williams-Ashman, H.G. and Schlenk, F. (Eds), The Biochemistry of Adenosylmethionine, Columbia University Press, New York, 1977, p. 251.

[EC 2.1.1.61 created 1982, modified 2012]

EC 2.1.1.62

Accepted name: mRNA (2'-O-methyladenosine-N6-)-methyltransferase

Reaction: S-adenosyl-L-methionine + a 5-(N7-methyl 5-triphosphoguanosine)-2'-O-methyladenosine-[mRNA] = S-adenosyl-L-homocysteine + a 5-(N7-methyl 5-triphosphoguanosine)-N6,2'-O-dimethyladenosine-[mRNA]

Glossary: a 5-(N7-methyl 5-triphosphoguanosine)-2'-O-methyladenosine-[mRNA] = m7G(5')pppAm-[mRNA]
a 5-(N7-methyl 5-triphosphoguanosine)-N6,2'-O-dimethyladenosine-[mRNA] = m7G(5')pppm6Am-[mRNA]

Other name(s): messenger ribonucleate 2'-O-methyladenosine NG-methyltransferase

Systematic name: S-adenosyl-L-methionine:mRNA (2'-O-methyladenosine-N6-)-methyltransferase

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 68009-87-0

References:

1. Keith, J.M., Ensinger, M.J. and Moss, B. HeLa cell RNA (2'-O-methyladenosine-N6-)-methyltransferase specific for the capped 5'-end of messenger RNA. J. Biol. Chem. 253 (1978) 5033-5039. [PMID: 670176]

2. Mauer, J., Luo, X., Blanjoie, A., Jiao, X., Grozhik, A.V., Patil, D.P., Linder, B., Pickering, B.F., Vasseur, J.J., Chen, Q., Gross, S.S., Elemento, O., Debart, F., Kiledjian, M. and Jaffrey, S.R. Reversible methylation of m6Am in the 5' cap controls mRNA stability. Nature 541 (2017) 371-375. [PMID: 28002401]

[EC 2.1.1.62 created 1982]

EC 2.1.1.63

Accepted name: methylated-DNA—[protein]-cysteine S-methyltransferase

Reaction: (1) DNA (containing 6-O-methylguanine) + protein L-cysteine = DNA (without 6-O-methylguanine) + protein S-methyl-L-cysteine
(2) DNA (containing 4-O-methylthymine) + protein L-cysteine = DNA (without 4-O-methylthymine) + protein S-methyl-L-cysteine

Other name(s): ada (gene name); ogt (gene name); MGT1 (gene name); MGMT (gene name)

Systematic name: DNA-6-O-methylguanine/DNA-4-O-methylthymine:[protein]-L-cysteine S-methyltransferase

Comments: This protein is involved in the repair of methylated DNA. Unlike EC 3.2.2.20, DNA-3-methyladenine glycosidase I and EC 3.2.2.21, DNA-3-methyladenine glycosidase II, which remove the methylated base leaving an apurinic/apyrimidinic site, this enzyme transfers the methyl group from the methylated DNA to an internal cysteine residue, leaving an intact nucleotide. Since the methyl transfer is irreversible, the enzyme can only catalyse a single turnover.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 77271-19-3

References:

1. Foote, R.S., Mitra, S. and Pal, B.C. Demethylation of O6-methylguanine in a synthetic DNA polymer by an inducible activity in Escherichia coli. Biochem. Biophys. Res. Commun. 97 (1980) 654-659. [PMID: 7008792]

2. Olsson, M. and Lindehl, T. Repair of alkylated DNA in Escherichia coli. Methyl group transfer from O6-methylguanine to a protein cysteine residue. J. Biol. Chem. 255 (1980) 10569-10571. [PMID: 7000780]

3. McCarthy, T.V. and Lindahl, T. Methyl phosphotriesters in alkylated DNA are repaired by the Ada regulatory protein of E. coli. Nucleic Acids Res. 13 (1985) 2683-2698. [PMID: 2987862]

4. Potter, P.M., Wilkinson, M.C., Fitton, J., Carr, F.J., Brennand, J., Cooper, D.P. and Margison, G.P. Characterisation and nucleotide sequence of ogt, the O6-alkylguanine-DNA-alkyltransferase gene of E. coli. Nucleic Acids Res. 15 (1987) 9177-9193. [PMID: 2825131]

5. Rebeck, G.W., Smith, C.M., Goad, D.L. and Samson, L. Characterization of the major DNA repair methyltransferase activity in unadapted Escherichia coli and identification of a similar activity in Salmonella typhimurium. J. Bacteriol. 171 (1989) 4563-4568. [PMID: 2670886]

6. Koike, G., Maki, H., Takeya, H., Hayakawa, H. and Sekiguchi, M. Purification, structure, and biochemical properties of human O6-methylguanine-DNA methyltransferase. J. Biol. Chem. 265 (1990) 14754-14762. [PMID: 2394694]

7. Sassanfar, M., Dosanjh, M.K., Essigmann, J.M. and Samson, L. Relative efficiencies of the bacterial, yeast, and human DNA methyltransferases for the repair of O6-methylguanine and O4-methylthymine. Suggestive evidence for O4-methylthymine repair by eukaryotic methyltransferases. J. Biol. Chem. 266 (1991) 2767-2771. [PMID: 1993655]

8. Xiao, W., Derfler, B., Chen, J. and Samson, L. Primary sequence and biological functions of a Saccharomyces cerevisiae O6-methylguanine/O4-methylthymine DNA repair methyltransferase gene. EMBO J. 10 (1991) 2179-2186. [PMID: 2065659]

[EC 2.1.1.63 created 1982, modified 1983, modified 1999, modified 2003, modified 2017]

EC 2.1.1.64

Accepted name: 3-demethylubiquinol 3-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 3-demethylubiquinol-n = S-adenosyl-L-homocysteine + ubiquinol-n

For diagram of reaction click here.

Glossary: 3-demethylubiquinol-n = 3-hydroxy-2-methoxy-5-methyl-6-(all-trans-polyprenyl)-1,4-benzoquinol

Other name(s): 5-demethylubiquinone-9 methyltransferase; OMHMB-methyltransferase; 2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone methyltransferase; S-adenosyl-L-methionine:2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone-O-methyltransferase; COQ3 (gene name); Coq3 O-methyltransferase; 3-demethylubiquinone-9 3-methyltransferase; ubiG (gene name, ambiguous)

Systematic name: S-adenosyl-L-methionine:3-hydroxy-2-methoxy-5-methyl-6-(all-trans-polyprenyl)-1,4-benzoquinol 3-O-methyltransferase

Comments: This enzyme is involved in ubiquinone biosynthesis. Ubiquinones from different organisms have a different number of prenyl units (for example, ubiquinone-6 in Saccharomyces, ubiquinone-9 in rat and ubiquinone-10 in human), and thus the natural substrate for the enzymes from different organisms has a different number of prenyl units. However, the enzyme usually shows a low degree of specificity regarding the number of prenyl units. For example, the human COQ3 enzyme can restore biosynthesis of ubiquinone-6 in coq3 deletion mutants of yeast [3]. The enzymes from yeast, Escherichia coli and rat also catalyse the methylation of 3,4-dihydroxy-5-all-trans-polyprenylbenzoate [3] (a reaction that is classified as EC 2.1.1.114, polyprenyldihydroxybenzoate methyltransferase).

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 63774-48-1

References:

1. Houser, R.M. and Olson, R.E. 5-Demethylubiquinone-9-methyltransferase from rat liver mitochondria. Characterization, localization, and solubilization. J. Biol. Chem. 252 (1977) 4017-4021. [PMID: 863914]

2. Leppik, R.A., Stroobant, P., Shineberg, B., Young, I.G. and Gibson, F. Membrane-associated reactions in ubiquinone biosynthesis. 2-Octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone methyltransferase. Biochim. Biophys. Acta 428 (1976) 146-156. [PMID: 769831]

3. Poon, W.W., Barkovich, R.J., Hsu, A.Y., Frankel, A., Lee, P.T., Shepherd, J.N., Myles, D.C. and Clarke, C.F. Yeast and rat Coq3 and Escherichia coli UbiG polypeptides catalyze both O-methyltransferase steps in coenzyme Q biosynthesis. J. Biol. Chem. 274 (1999) 21665-21672. [PMID: 10419476]

4. Jonassen, T. and Clarke, C.F. Isolation and functional expression of human COQ3, a gene encoding a methyltransferase required for ubiquinone biosynthesis. J. Biol. Chem. 275 (2000) 12381-12387. [PMID: 10777520]

[EC 2.1.1.64 created 1982, modified 2011]

EC 2.1.1.65

Accepted name: licodione 2'-O-methyltransferase

Reaction: S-adenosyl-L-methionine + licodione = S-adenosyl-L-homocysteine + 2'-O-methyllicodione

For diagram click here.

Systematic name: S-adenosyl-L-methionine:licodione 2'-O-methyltransferase

Comments: As well as licodione [1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)-1,3-propanedione], the 2"-hydroxy-derivative and isoliquiritigenin can act as acceptors, but more slowly.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 77000-07-8

References:

1. Ayabe, S.-I., Yoshikawa, T., Kobayashi, M. and Furuya, T. Biosynthesis of retrochalcone, echinatin: involvement of O-methyltransferase to licodione. Phytochemistry 19 (1980) 2331-2336.

[EC 2.1.1.65 created 1983]

[EC 2.1.1.66 Deleted entry: rRNA (adenosine-2'-O-)-methyltransferase. Now covered by EC 2.1.1.230, 23S rRNA (adenosine1067-2-O)-methyltransferase. (EC 2.1.1.66 created 1984, deleted 2013)]

EC 2.1.1.67

Accepted name: thiopurine S-methyltransferase

Reaction: S-adenosyl-L-methionine + a thiopurine = S-adenosyl-L-homocysteine + a thiopurine S-methylether

Other name(s): mercaptopurine methyltransferase; thiopurine methyltransferase; 6-thiopurine transmethylase; TPMT

Systematic name: S-adenosyl-L-methionine:thiopurine S-methyltransferase

Comments: Also acts, more slowly, on thiopyrimidines and aromatic thiols. Not identical with EC 2.1.1.9 thiol S-methyltransferase.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 67339-09-7

References:

1. Remy, C.N. Metabolism of thiopyrimidines and thiopurines. S-Methylation with S-adenosylmethionine transmethylase and catabolism in mammalian tissues. J. Biol. Chem. 238 (1963) 1078-1084.

2. Woodson, L.C., Ames, M.M., Selassie, C.D, Hansch, C. and Weinshilbaum, R.M. Thiopurine methyltransferase. Aromatic thiol substrates and inhibition by benzoic acid derivatives. Mol. Pharmacol. 24 (1983) 471-478. [PMID: 6633508]

3. Woodson, L.C. and Weinshilbaum, R.M. Human kidney thiopurine methyltransferase. Purification and biochemical properties. Biochem. Pharmacol. 32 (1983) 819-826. [PMID: 6838629]

[EC 2.1.1.67 created 1984]

EC 2.1.1.68

Accepted name: caffeate O-methyltransferase

Reaction: S-adenosyl-L-methionine + 3,4-dihydroxy-trans-cinnamate = S-adenosyl-L-homocysteine + 3-methoxy-4-hydroxy-trans-cinnamate

Other name(s): caffeate methyltransferase; caffeate 3-O-methyltransferase; S-adenosyl-L-methionine:caffeic acid-O-methyltransferase

Systematic name: S-adenosyl-L-methionine:3,4-dihydroxy-trans-cinnamate 3-O-methyltransferase

Comments: 3,4-Dihydroxybenzaldehyde and catechol can act as acceptors, but more slowly.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 50936-45-3

References:

1. Ebel, J., Schaller-Hekeler, B., Knobloch, K.-H., Wellman, E., Grisebach, H. and Hahlbrock, K. Coordinated changes in enzyme activities of phenylpropanoid metabolism during the growth of soybean cell suspension cultures. Biochim. Biophys. Acta 362 (1974) 417-424. [PMID: 4472044]

2. Poulton, J.E. and Butt, V.S. Purification and properties of S-adenosyl-L-methionine: caffeic acid O-methyltransferase from leaves of spinach beet (Beta vulgaris L). Biochim. Biophys. Acta 403 (1975) 301-314. [PMID: 241400]

3. Shimada, M., Kuroda, H. and Higuchi, T. Evidence for the formation of methoxyl groups of ferulic and sinapic acid in Bambusa by the same O-methyltransferase. Phytochemistry 12 (1973) 2873-2875.

[EC 2.1.1.68 created 1984]

EC 2.1.1.69

Accepted name: 5-hydroxyfuranocoumarin 5-O-methyltransferase

Reaction: (1) S-adenosyl-L-methionine + a 5-hydroxyfurocoumarin = S-adenosyl-L-homocysteine + a 5- methoxyfurocoumarin (general reaction)
(2) S-adenosyl-L-methionine + bergaptol = S-adenosyl-L-homocysteine + bergapten

For diagram click here.

Glossary: bergaptol = 5-hydroxypsoralen
O-methylbergaptol = bergapten = 5-methoxypsoralen

Other name(s): furanocoumarin 5-methyltransferase; furanocoumarin 5-O-methyltransferase; bergaptol 5-O-methyltransferase; bergaptol O-methyltransferase; bergaptol methyltransferase; S-adenosyl-L-methionine:bergaptol O-methyltransferase; BMT; S-adenosyl-L-methionine:5-hydroxyfuranocoumarin 5-O-methyltransferase

Systematic name: S-adenosyl-L-methionine:5-hydroxyfurocoumarin 5-O-methyltransferase

Comments: Converts bergaptol into bergapten, which has therapeutic potential in the treatment of psoriasis as it has photosensitizing and antiproliferative activities [4]. The enzyme methylates the 5-hydroxy group of some hydroxy- and methylcoumarins, such as 5-hydroxyxanthotoxin [3], but has little activity on non-coumarin phenols [1]. Caffeate, 5-hydroxyferulate and daphnetin are not substrates [4]. Cu2+, Zn2+ and Co2+ cause enzyme inhibition [4]. (see also EC 2.1.1.70, 8-hydroxyfuranocoumarin 8-O-methyltransferase)

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 67339-12-2, 101637-31-4

References:

1. Thompson, H.J., Sharma, S.K. and Brown, S.A. O-Methyltransferases of furanocoumarin biosynthesis. Arch. Biochem. Biophys. 188 (1978) 272-281. [PMID: 28084]

2. Sharma, S.K., Garrett, J.M. and Brown, S.A. Separation of the S-adenosylmethionine: 5- and 8-hydroxyfuranocoumarin O-methyltransferases of Ruta graveolens L. by general ligand affinity chromatography. Z. Naturforsch. [C] 34C (1979) 387-391. [PMID: 156999]

3. Hauffe, K.D., Hahlbrock, K. and Scheel, D. Elicitor-stimulated furanocoumarin biosynthesis in cultured parsley cells - S-adenosyl-L-methionine-bergaptol and S-adenosyl-L-methionine-xanthotoxol O-methyltransferases. Z. Naturforsch. C: Biosci. 41 (1986) 228-239.

4. Hehmann, M., Lukacin, R., Ekiert, H. and Matern, U. Furanocoumarin biosynthesis in Ammi majus L. Cloning of bergaptol O-methyltransferase. Eur. J. Biochem. 271 (2004) 932-940. [PMID: 15009205]

[EC 2.1.1.69 created 1984 (EC 2.1.1.92 created 1989, incorporated 2006), modified 2006]

EC 2.1.1.70

Accepted name: 8-hydroxyfuranocoumarin 8-O-methyltransferase

Reaction: (1) S-adenosyl-L-methionine + an 8-hydroxyfurocoumarin = S-adenosyl-L-homocysteine + an 8-methoxyfurocoumarin (general reaction)
(2) S-adenosyl-L-methionine + xanthotoxol = S-adenosyl-L-homocysteine + xanthotoxin

For diagram of reaction, click here

Glossary: xanthotoxin = O-methylxanthotoxol = 8-methoxypsoralen
xanthotoxol = 8-hydroxypsoralen

Other name(s): furanocoumarin 8-methyltransferase; furanocoumarin 8-O-methyl-transferase; xanthotoxol 8-O-methyltransferase; XMT; 8-hydroxyfuranocoumarin 8-O-methyltransferase; SAM:xanthotoxol O-methyltransferase; S-adenosyl-L-methionine:8-hydroxyfuranocoumarin 8-O-methyltransferase; xanthotoxol methyltransferase; xanthotoxol O-methyltransferase; S-adenosyl-L-methionine:xanthotoxol O-methyltransferase; S-adenosyl-L-methionine-xanthotoxol O-methyltransferase

Systematic name: S-adenosyl-L-methionine:8-hydroxyfurocoumarin 8-O-methyltransferase

Comments: Converts xanthotoxol into xanthotoxin, which has therapeutic potential in the treatment of psoriasis as it has photosensitizing and antiproliferative activities [4]. Methylates the 8-hydroxy group of some hydroxy- and methylcoumarins, but has little activity on non-coumarin phenols (see also EC 2.1.1.69, 5-hydroxyfuranocoumarin 5-O-methyltransferase).

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 67339-13-3

References:

1. Thompson, H.J., Sharma, S.K. and Brown, S.A. O-Methyltransferases of furanocoumarin biosynthesis. Arch. Biochem. Biophys. 188 (1978) 272-281. [PMID: 28084]

2. Hauffe, K.D., Hahlbrock, K. and Scheel, D. Elicitor-stimulated furanocoumarin biosynthesis in cultured parsley cells - S-adenosyl-L-methionine-bergaptol and S-adenosyl-L-methionine-xanthotoxol O-methyltransferases. Z. Naturforsch. C: Biosci. 41 (1986) 228-239.

3. Sharma, S.K., Garrett, J.M. and Brown, S.A. Separation of the S-adenosylmethionine: 5- and 8-hydroxyfuranocoumarin O-methyltransferases of Ruta graveolens L. by general ligand affinity chromatography. Z. Naturforsch. [C] 34C (1979) 387-391. [PMID: 156999]

4. Hehmann, M., Lukačin, R., Ekiert, H. and Matern, U. Furanocoumarin biosynthesis in Ammi majus L. Cloning of bergaptol O-methyltransferase. Eur. J. Biochem. 271 (2004) 932-940. [PMID: 15009205]

Note For reference 4 an accent may not be seen. č is c-hacek.

[EC 2.1.1.70 created 1984, modified 2006 (EC 2.1.1.93 created 2006, incorporated 2008)]

EC 2.1.1.71

Accepted name: phosphatidyl-N-methylethanolamine N-methyltransferase

Reaction: S-adenosyl-L-methionine + phosphatidyl-N-methylethanolamine = S-adenosyl-L-homocysteine + phosphatidyl-N-dimethylethanolamine

Other name(s): phosphatidylmonomethylethanolamine methyltransferase; methyltransferase II; phospholipid methyltransferase; PLMT; phosphatidyl-N-methylethanolamine methyltransferase; phosphatidyl-N-monomethylethanolamine methyltransferase; phosphatidylethanolamine methyltransferase I; phosphatidylmonomethylethanolamine methyltransferase

Systematic name: S-adenosyl-L-methionine:phosphatidyl-N-methylethanolamine N-methyltransferase

Comments: The enzyme also catalyses the transfer of a further methyl group, producing phosphatidylcholine.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 67167-73-1

References:

1. Hirata, F., Viveros, O.H., Diliberto, E.J., Jr. and Axelrod, J. Identification and properties of two methyltransferases in conversion of phosphatidylethanolamine to phosphatidylcholine. Proc. Natl. Acad. Sci. USA 75 (1978) 1718-1721. [PMID: 25437]

2. Schneider, W.J. and Vance, D.E. Conversion of phosphatidylethanolamine to phosphatidylcholine in rat liver. Partial purification and characterization of the enzymatic activities. J. Biol. Chem. 254 (1979) 3886-3891. [PMID: 438165]

[EC 2.1.1.71 created 1984]

EC 2.1.1.72

Accepted name: site-specific DNA-methyltransferase (adenine-specific)

Reaction: S-adenosyl-L-methionine + DNA adenine = S-adenosyl-L-homocysteine + DNA 6-methylaminopurine

Other name(s): modification methylase; restriction-modification system

Comments: This is a large group of enzymes, most of which, with enzymes of similar site specificity listed as EC 3.1.21.3 type 1 site-specific deoxyribonuclease, EC 3.1.21.4 type II site-specific deoxyribonuclease or EC 3.1.21.5 type III site-specific deoxyribonuclease, form so-called 'restriction-modification systems'. A complete listing of all of these enzymes has been produced by R.J. Roberts and is available on-line at http://rebase.neb.com/rebase/rebase.html.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 69553-52-2

References:

1. Kessler, C. and Manta, V. Specificity of restriction endonucleases and DNA modification methyltransferases: a review (Edition 3). Gene 92 (1990) 1-248. [PMID: 2172084]

2. Roberts, R.J. Restriction enzymes and their isoschizomers. Nucleic Acids Res. 18 (1990) 2331-2365. [PMID: 2159140]

3. Yuan, R. Structure and mechanism of multifunctional restriction endonucleases. Annu. Rev. Biochem. 50 (1981) 285-319. [PMID: 6267988]

[EC 2.1.1.72 created 1984]

[EC 2.1.1.73 Deleted entry: site-specific DNA-methyltransferase (cytosine-specific). Reaction is that of EC 2.1.1.37, DNA (cytosine-5-)-methyltransferase. (EC 2.1.1.73 created 1984, deleted 2003)]

EC 2.1.1.74

Accepted name: methylenetetrahydrofolate—tRNA-(uracil54-C5)-methyltransferase (FADH2-oxidizing)

Reaction: 5,10-methylenetetrahydrofolate + uracil54 in tRNA + FADH2 = tetrahydrofolate + 5-methyluracil54 in tRNA + FAD

Glossary: Ψ = pseudouridine
T = ribothymidine = 5-methyluridine

Other name(s): folate-dependent ribothymidyl synthase; methylenetetrahydrofolate-transfer ribonucleate uracil 5-methyltransferase; 5,10-methylenetetrahydrofolate:tRNA-UPsiC (uracil-5-)-methyl-transferase; 5,10-methylenetetrahydrofolate:tRNA (uracil-5-)-methyl-transferase; TrmFO; folate/FAD-dependent tRNA T54 methyltransferase

Systematic name: 5,10-methylenetetrahydrofolate:tRNA (uracil54-C5)-methyltransferase

Comments: Up to 25% of the bases in mature tRNA are post-translationally modified or hypermodified. One almost universal post-translational modification is the conversion of U54 into ribothymidine in the TPsiC loop, and this modification is found in most species studied to date [2]. Unlike this enzyme, which uses 5,10-methylenetetrahydrofolate and FADH2 to supply the atoms for methylation of U54, EC 2.1.1.35, tRNA (uracil54-C5)-methyltransferase, uses S-adenosyl-L-methionine.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 56831-74-4

References:

1. Delk, A.S., Nagle, D.P., Jr. and Rabinowitz, J.C. Methylenetetrahydrofolate-dependent biosynthesis of ribothymidine in transfer RNA of Streptococcus faecalis. Evidence for reduction of the 1-carbon unit by FADH2. J. Biol. Chem. 255 (1980) 4387-4390. [PMID: 6768721]

2. Becker, H.F., Motorin, Y., Sissler, M., Florentz, C. and Grosjean, H. Major identity determinants for enzymatic formation of ribothymidine and pseudouridine in the TΨ-loop of yeast tRNAs. J. Mol. Biol. 274 (1997) 505-518. [PMID: 9417931]

3. Nishimasu, H., Ishitani, R., Yamashita, K., Iwashita, C., Hirata, A., Hori, H. and Nureki, O. Atomic structure of a folate/FAD-dependent tRNA T54 methyltransferase. Proc. Natl. Acad. Sci. USA 106 (2009) 8180-8185. [PMID: 19416846]

[EC 2.1.1.74 created 1983 as EC 2.1.2.12, transferred 1984 to EC 2.1.1.74, modified 2011]

EC 2.1.1.75

Accepted name: apigenin 4'-O-methyltransferase

Reaction: S-adenosyl-L-methionine + apigenin = S-adenosyl-L-homocysteine + acacetin

For diagram click here.

Glossary: apigenin = 4′,5,7-trihydroxyflavone
acacetin = 4′-methoxy-5,7-dihydroxyflavone
naringenin = 4′,5,7-trihydroxyflavan-4-one

Other name(s): flavonoid O-methyltransferase; flavonoid methyltransferase

Systematic name: S-adenosyl-L-methionine:5,7,4'-trihydroxyflavone 4'-O-methyltransferase

Comments: Converts apigenin into acacetin. Naringenin can also act as an acceptor, but more slowly.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 118251-36-8

References:

1. Kuroki, G. and Poulton, J.E. The para-O-methylation of apigenin to acacetin by cell-free extracts of Robinia pseudoacacia L. Z. Naturforsch. C: Biosci. 36 (1981) 916-920.

[EC 2.1.1.75 created 1984]

EC 2.1.1.76

Accepted name: quercetin 3-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 3,5,7,3',4'-pentahydroxyflavone = S-adenosyl-L-homocysteine + 3-methoxy-5,7,3',4'-tetrahydroxyflavone

For diagram click here.

Other name(s): flavonol 3-O-methyltransferase; flavonoid 3-methyltransferase

Systematic name: S-adenosyl-L-methionine:3,5,7,3',4'-pentahydroxyflavone 3-O-methyltransferase

Comments: Specific for quercetin. Related enzymes bring about the 3-O-methylation of other flavonols, such as galangin and kaempferol.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 81295-55-8

References:

1. De Luca, V., Brunet, G., Khouri, H., Ibrahim, R. and Hrazdina, G. Flavonol 3-O-methyltransferase in plant-tissues. Z. Naturforsch. 37 (1982) 134-135.

2. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. I. Partial purification and some properties of S-adenosyl-L-methionine:flavonol 3-, 6-, 7-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 596-605. [PMID: 3994393]

3. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. II. Substrate interaction and product inhibition studies of flavonol 3-, 6-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 606-618. [PMID: 3994394]

4. Ibrahim, R.K. and De Luca,V. Polymethylated flavonol synthesis is catalyzed by distinct O-methyltransferases. Naturwissenschaften 69 (1982) 41-42.

[EC 2.1.1.76 created 1984]

EC 2.1.1.77

Accepted name: protein-L-isoaspartate(D-aspartate) O-methyltransferase

Reaction: S-adenosyl-L-methionine + protein L-isoaspartate = S-adenosyl-L-homocysteine + protein L-isoaspartate α-methyl ester

Other name(s): protein-L-isoaspartate O-methyltransferase; protein-β-aspartate O-methyltransferase; D-aspartyl/L-isoaspartyl methyltransferase; L-isoaspartyl/D-aspartyl protein carboxyl methyltransferase; protein (D-aspartate) methyltransferase; protein D-aspartate methyltransferase; protein L-isoaspartate methyltransferase; protein L-isoaspartyl methyltransferase; protein O-methyltransferase (L-isoaspartate); L-aspartyl/L-isoaspartyl protein methyltransferase

Systematic name: S-adenosyl-L-methionine:protein-L-isoaspartate O-methyltransferase

Comments: D-Aspartate (but not L-aspartate) residues in proteins can also act as acceptors. Previously also listed as EC 2.1.1.24.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 105638-50-4

References:

1. Aswad, D.W. and Johnson, B.A. The unusual substrate-specificity of eukaryotic protein carboxyl methyltransferases. Trends Biochem. Sci. 12 (1987) 155-158.

2. Clarke, S. Protein carboxyl methyltransferases: two distinct classes of enzymes. Annu. Rev. Biochem. 54 (1985) 479-506. [PMID: 3896126]

3. Kim, S. and Paik, W.K. Purification and properties of protein methylase II. J. Biol. Chem. 245 (1970) 1806-1813. [PMID: 5438363]

4. Ota, I.M., Ding, L. and Clarke, S. Methylation at specific altered aspartyl and asparaginyl residues in glucagon by the erythrocyte protein carboxyl methyltransferase. J. Biol. Chem. 262 (1987) 8522-8531. [PMID: 3597386]

[EC 2.1.1.77 created 1984, modified 1989 (EC 2.1.1.24 created 1972, modified 1983, modified 1989, part incorporated 1992)]

EC 2.1.1.78

Accepted name: isoorientin 3'-O-methyltransferase

Reaction: S-adenosyl-L-methionine + isoorientin = S-adenosyl-L-homocysteine + isoscoparin

Other name(s): isoorientin 3'-methyltransferase

Systematic name: S-adenosyl-L-methionine:isoorientin 3'-O-methyltransferase

Comments: Also acts on isoorientin 2"-O-rhamnoside. Involved in the biosynthesis of flavones.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 83061-51-2

References:

1. van Brederode, J., Kamps-Heinsbroek, R. and Mastenbroek, O. Biochemical and ontogenetic evidence that the ferulic acid and isoscoparin formation in silene are catalyzed by different enzymes. Z. Pflanzenphysiol. 106 (1982) 43-53.

[EC 2.1.1.78 created 1986]

EC 2.1.1.79

Accepted name: cyclopropane-fatty-acyl-phospholipid synthase

Reaction: S-adenosyl-L-methionine + phospholipid olefinic fatty acid = S-adenosyl-L-homocysteine + phospholipid cyclopropane fatty acid

Other name(s): cyclopropane synthetase; unsaturated-phospholipid methyltransferase; cyclopropane synthase; cyclopropane fatty acid synthase; cyclopropane fatty acid synthetase; CFA synthase

Systematic name: S-adenosyl-L-methionine:unsaturated-phospholipid methyltransferase (cyclizing)

Comments: The enzyme adds a methylene group across the 9,10 position of a δ9-olefinic acyl chain in phosphatidylethanolamine or, more slowly, phosphatidylglycerol or phosphatidylinositol, forming a cyclopropane derivative (cf. EC 2.1.1.16 methylene-fatty-acyl-phospholipid synthase).

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 51845-48-8

References:

1. Chung, A.E. and Law, J.H. Cyclopropane fatty acid synthetase: Partial purification and properties. Biochemistry 3 (1964) 967-974.

2. Zalkin, H., Law, J.H. and Goldfine, H. Enzymatic synthesis of cyclopropane fatty acids catalyzed by bacterial extracts. J. Biol. Chem. 238 (1963) 1242-1248.

[EC 2.1.1.79 created 1986]

EC 2.1.1.80

Accepted name: protein-glutamate O-methyltransferase

Reaction: S-adenosyl-L-methionine + protein L-glutamate = S-adenosyl-L-homocysteine + protein L-glutamate methyl ester

Other name(s): methyl-accepting chemotaxis protein O-methyltransferase; S-adenosylmethionine-glutamyl methyltransferase; methyl-accepting chemotaxis protein methyltransferase II; S-adenosylmethionine:protein-carboxyl O-methyltransferase; protein methylase II; MCP methyltransferase I; MCP methyltransferase II; protein O-methyltransferase; protein(aspartate)methyltransferase; protein(carboxyl)methyltransferase; protein carboxyl-methylase; protein carboxyl-O-methyltransferase; protein carboxylmethyltransferase II; protein carboxymethylase; protein carboxymethyltransferase; protein methyltransferase II

Systematic name: S-adenosyl-L-methionine:protein-L-glutamate O-methyltransferase

Comments: Forms ester groups with L-glutamate residues in a number of membrane proteins.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9055-09-8

References:

1. Burgess-Cassler, A., Ulla, A.H.J. and Ordal, G.W. Purification and characterization of Bacillus subtilis methyl-accepting chemotaxis protein methyltransferase II. J. Biol. Chem. 257 (1982) 8412-8417. [PMID: 6806296]

2. Kleene, S.J., Toews, M.L. and Adler, J. Isolation of glutamic acid methyl ester from an Escherichia coli membrane protein involved in chemotaxis. J. Biol. Chem. 252 (1977) 3214-3218. [PMID: 16888]

3. Simms, S.A., Stock, A.M. and Stock, J.B. Purification and characterization of the S-adenosylmethionine:glutamyl methyltransferase that modifies membrane chemoreceptor proteins in bacteria. J. Biol. Chem. 262 (1987) 8537-8543. [PMID: 3298235]

4. Springer, W.R. and Koshland, D.E., Jr. Identification of a protein methyltransferase as the cheR gene product in the bacterial sensing system. Proc. Natl. Acad. Sci. USA 74 (1977) 533-537. [PMID: 322131]

[EC 2.1.1.80 created 1989 (EC 2.1.1.24 created 1972, modified 1983, modified 1989, part incorporated 1992)]

[EC 2.1.1.81 Deleted entry: nicotine N-methyltransferase. Now included with EC 2.1.1.49 amine N-methyltransferase. (EC 2.1.1.81 created 1989, deleted 1990)]

EC 2.1.1.82

Accepted name: 3-methylquercetin 7-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxy-3-methoxyflavone = S-adenosyl-L-homocysteine + 5,3',4'-trihydroxy-3,7-dimethoxyflavone

For diagram click here.

Other name(s): flavonol 7-O-methyltransferase; flavonol 7-methyltransferase; 7-OMT; S-adenosyl-L-methionine:3',4',5,7-tetrahydroxy-3-methoxyflavone 7-O-methyltransferase; 3-methylquercitin 7-O-methyltransferase [mis-spelt]

Systematic name: S-adenosyl-L-methionine:5,7,3',4'-tetrahydroxy-3-methoxyflavone 7-O-methyltransferase

Comments: Involved with EC 2.1.1.76 quercetin 3-O-methyltransferase and EC 2.1.1.83 3,7-dimethylquercetin 4'-O-methyltransferase in the methylation of quercetin to 3,7,4'-trimethylquercetin in Chrysosplenium americanum. Does not act on flavones, dihydroflavonols, or their glucosides.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 97089-67-3

References:

1. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. I. Partial purification and some properties of S-adenosyl-L-methionine:flavonol 3-, 6-, 7-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 596-605. [PMID: 3994393]

[EC 2.1.1.82 created 1989]

EC 2.1.1.83

Accepted name: 3,7-dimethylquercetin 4'-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 5,3',4'-trihydroxy-3,7-dimethoxyflavone = S-adenosyl-L-homocysteine + 5,3'-dihydroxy-3,7,4'-trimethoxyflavone

For diagram click here.

Other name(s): flavonol 4'-O-methyltransferase; flavonol 4'-methyltransferase; 4'-OMT; S-adenosyl-L-methionine:3',4',5-trihydroxy-3,7-dimethoxyflavone 4'-O-methyltransferase; 3,7-dimethylquercitin 4'-O-methyltransferase [mis-spelt]

Systematic name: S-adenosyl-L-methionine:5,3',4'-trihydroxy-3,7-dimethoxyflavone 4'-O-methyltransferase

Comments: 3,7-Dimethylquercetagetin can also act as acceptor. Involved with EC 2.1.1.76 quercetin 3-O-methyltransferase and EC 2.1.1.82 3-methylquercetin 7-O-methyltransferase in the methylation of quercetin to 3,7,4'-trimethylquercetin in Chrysosplenium americanum. Does not act on flavones, dihydroflavonols, or their glucosides.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 96477-60-0

References:

1. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. I. Partial purification and some properties of S-adenosyl-L-methionine:flavonol 3-, 6-, 7-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 596-605. [PMID: 3994393]

2. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. II. Substrate interaction and product inhibition studies of flavonol 3-, 6-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 606-618. [PMID: 3994394]

[EC 2.1.1.83 created 1989]

EC 2.1.1.84

Accepted name: methylquercetagetin 6-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 5,6,3',4'-tetrahydroxy-3,7-dimethoxyflavone = S-adenosyl-L-homocysteine + 5,3',4'-trihydroxy-3,6,7-trimethoxyflavone

Other name(s): flavonol 6-O-methyltransferase; flavonol 6-methyltransferase; 6-OMT; S-adenosyl-L-methionine:3',4',5,6-tetrahydroxy-3,7-dimethoxyflavone 6-O-methyltransferase

Systematic name: S-adenosyl-L-methionine:3',4',5,6-tetrahydroxy-3,7-dimethoxyflavone 6-O-methyltransferase

Comments: The enzymes from Chrysosplenium americanum also methylates 3,7,3'-trimethylquercetagetin at the 6-position. Does not act on flavones, dihydroflavonols, or their glucosides.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 97089-68-4

References:

1. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. I. Partial purification and some properties of S-adenosyl-L-methionine:flavonol 3-, 6-, 7-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 596-605. [PMID: 3994393]

2. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. II. Substrate interaction and product inhibition studies of flavonol 3-, 6-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 606-618. [PMID: 3994394]

[EC 2.1.1.84 created 1989]

EC 2.1.1.85

Accepted name: protein-histidine N-methyltransferase

Reaction: S-adenosyl-L-methionine + protein L-histidine = S-adenosyl-L-homocysteine + protein Nτ-methyl-L-histidine

Other name(s): protein methylase IV; protein (histidine) methyltransferase; actin-specific histidine methyltransferase; S-adenosyl methionine:protein-histidine N-methyltransferase

Systematic name: S-adenosyl-L-methionine:protein-L-histidine N-tele-methyltransferase

Comments: Highly specific for histidine residues, for example, in actin.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 108022-17-9

References:

1. Vijayasarathy, C. and Narasinga Rao, B.S. Partial purification and characterisation of S-adenosylmethionine:protein-histidine N-methyltransferase from rabbit skeletal muscle. Biochim. Biophys. Acta 923 (1987) 156-165. [PMID: 3801515]

[EC 2.1.1.85 created 1989]

EC 2.1.1.86

Accepted name: tetrahydromethanopterin S-methyltransferase

Reaction: 5-methyl-5,6,7,8-tetrahydromethanopterin +CoM + 2 Na+in = 5,6,7,8-tetrahydromethanopterin + 2-(methylsulfanyl)ethane-1-sulfonate + 2 Na+out

For diagram of reaction click here.

Glossary: CoM = coenzyme M = 2-sulfanylethane-1-sulfonate
tetrahydromethanopterin = 1-(4-{(1R)-1-[(6S,7S)-2-amino-7-methyl-4-oxo-3,4,5,6,7,8-hexahydropteridin-6-yl]ethylamino}phenyl)-1-deoxy-5-O-{5-O-[(1S)-1,3-dicarboxypropylphosphonato]-α-D-ribofuranosyl}-D-ribitol

Other name(s): tetrahydromethanopterin methyltransferase; mtrA-H (gene names); cmtA (gene name)

Systematic name: 5-methyl-5,6,7,8-tetrahydromethanopterin:2-sulfanylethane-1-sulfonate 2-methyltransferase

Comments: Involved in the formation of methane from CO2 in methanogenic archaea. The reaction involves the export of one or two sodium ions. The enzyme from the archaeon Methanobacterium thermoautotrophicum is a membrane-associated multienzyme complex composed of eight different subunits, and contains a 5'-hydroxybenzimidazolyl-cobamide prosthetic group, to which the methyl group is attached during the transfer. A soluble enzyme that is induced by the presence of CO has been reported as well [6].

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, UM-BBD, CAS registry number: 103406-60-6

References:

1. Sauer, F.D. Tetrahydromethanopterin methyltransferase, a component of the methane synthesizing complex of Methanobacterium thermoautotrophicum. Biochem. Biophys. Res. Commun. 136 (1986) 542-547. [PMID: 3085670]

2. Gartner, P., Ecker, A., Fischer, R., Linder, D., Fuchs, G. and Thauer, R.K. Purification and properties of N5-methyltetrahydromethanopterin:coenzyme M methyltransferase from Methanobacterium thermoautotrophicum. Eur. J. Biochem. 213 (1993) 537-545. [PMID: 8477726]

3. Weiss, D.S., Gartner, P. and Thauer, R.K. The energetics and sodium-ion dependence of N5-methyltetrahydromethanopterin:coenzyme M methyltransferase studied with cob(I)alamin as methyl acceptor and methylcob(III)alamin as methyl donor. Eur. J. Biochem. 226 (1994) 799-809. [PMID: 7813469]

4. Harms, U., Weiss, D.S., Gartner, P., Linder, D. and Thauer, R.K. The energy conserving N5-methyltetrahydromethanopterin:coenzyme M methyltransferase complex from Methanobacterium thermoautotrophicum is composed of eight different subunits. Eur. J. Biochem. 228 (1995) 640-648. [PMID: 7737157]

5. Gottschalk, G. and Thauer, R.K. The Na(+)-translocating methyltransferase complex from methanogenic archaea. Biochim. Biophys. Acta 1505 (2001) 28-36. [PMID: 11248186]

6. Vepachedu, V.R. and Ferry, J.G. Role of the fused corrinoid/methyl transfer protein CmtA during CO-dependent growth of Methanosarcina acetivorans. J. Bacteriol. 194 (2012) 4161-4168. [PMID: 22636775]

[EC 2.1.1.86 created 1989, modified 2000, modified 2017]

EC 2.1.1.87

Accepted name: pyridine N-methyltransferase

Reaction: S-adenosyl-L-methionine + pyridine = S-adenosyl-L-homocysteine + N-methylpyridinium

Other name(s): pyridine methyltransferase

Systematic name: S-adenosyl-L-methionine:pyridine N-methyltransferase

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 104327-10-8

References:

1. Damani, L.A., Shaker, M.S., Crooks, P.A., Godin, C.S. and Nwosu, C. N-Methylation and quaternization of pyridine in vitro by rabbit lung, liver and kidney N-methyltransferases: an S-adenosyl-L-methionine-dependent reaction. Xenobiotica 16 (1986) 645-650. [PMID: 3751119]

[EC 2.1.1.87 created 1989]

EC 2.1.1.88

Accepted name: 8-hydroxyquercetin 8-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 3,5,7,8,3',4'-hexahydroxyflavone = S-adenosyl-L-homocysteine + 3,5,7,3',4'-pentahydroxy-8-methoxyflavone

Other name(s): flavonol 8-O-methyltransferase; flavonol 8-methyltransferase; S-adenosyl-L-methionine:3,3',4',5,7,8-hexahydroxyflavone 8-O-methyltransferase; 8-hydroxyquercitin 8-O-methyltransferase [mis-spelt]

Systematic name: S-adenosyl-L-methionine:3,5,7,8,3',4'-hexahydroxyflavone 8-O-methyltransferase

Comments: Also acts on 8-hydroxykaempferol, but not on the glycosides of 8-hydroxyflavonols. An enzyme from the flower buds of Lotus corniculatus.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 99775-17-4

References:

1. Jay, M., De Luca, V. and Ibrahim, R.K. Purification, properties and kinetic mechanism of flavonol 8-O-methyltransferase from Lotus corniculatus L. Eur. J. Biochem. 153 (1985) 321-325. [PMID: 4076180]

[EC 2.1.1.88 created 1989]

EC 2.1.1.89

Accepted name: tetrahydrocolumbamine 2-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 5,8,13,13a-tetrahydrocolumbamine = S-adenosyl-L-homocysteine + tetrahydropalmatine

Other name(s): tetrahydrocolumbamine methyltransferase

Systematic name: S-adenosyl-L-methionine:5,8,13,13a-tetrahydrocolumbamine 2-O-methyltransferase

Comments: Involved in the biosynthesis of the berberine alkaloids.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 93792-09-7

References:

1. Beecher, C.W.W. and Kelleher, W.J. Enzymatic study of the late stages of protoberberine alkaloid biosynthesis. Tetrahedron Lett. 25 (1984) 4595-4598.

[EC 2.1.1.89 created 1989]

EC 2.1.1.90

Accepted name: methanol—corrinoid protein Co-methyltransferase

Reaction: methanol + a [Co(I) methanol-specific corrinoid protein] = a [methyl-Co(III) methanol-specific corrinoid protein] + H2O

Other name(s): methanol cobalamin methyltransferase; methanol:5-hydroxybenzimidazolylcobamide methyltransferase; MT 1 (ambiguous); methanol—5-hydroxybenzimidazolylcobamide Co-methyltransferase; mtaB (gene name)

Systematic name: methanol:5-hydroxybenzimidazolylcobamide Co-methyltransferase

Comments: The enzyme, which catalyses the transfer of methyl groups from methanol to a methanol-specific corrinoid protein (MtaC), is involved in methanogenesis from methanol. Methylation of the corrinoid protein requires the central cobalt to be in the Co(I) state. During methylation the cobalt is oxidized to the Co(III) state. Free cob(I)alamin can substitute for the corrinoid protein in vitro [2]. Inactivated by oxygen and other oxidizing agents, and reactivated by catalytic amounts of ATP and hydrogen.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 86611-98-5

References:

1. van der Meijden, P., te Brömmelstroet, B.W., Poirot, C.M., van der Drift, C. and Vogels, G.D. Purification and properties of methanol:5-hydroxybenzimidazolylcobamide methyltransferase from Methanosarcina barkeri. J. Bacteriol. 160 (1984) 629-635. [PMID: 6438059]

2. Sauer, K. and Thauer, R.K. Methanol:coenzyme M methyltransferase from Methanosarcina barkeri – substitution of the corrinoid harbouring subunit MtaC by free cob(I)alamin. Eur. J. Biochem. 261 (1999) 674-681. [PMID: 10215883]

[EC 2.1.1.90 created 1989, modified 2012]

EC 2.1.1.91

Accepted name: isobutyraldoxime O-methyltransferase

Reaction: S-adenosyl-L-methionine + 2-methylpropanal oxime = S-adenosyl-L-homocysteine + 2-methylpropanal O-methyloxime

Other name(s): aldoxime methyltransferase; S-adenosylmethionine:aldoxime O-methyltransferase; aldoxime O-methyltransferase

Systematic name: S-adenosyl-L-methionine:2-methylpropanal-oxime O-methyltransferase

Comments: Oximes of C4 to C6 aldehydes can act as acceptors; the most active substrate is 2-methylbutyroaldoxime.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 95471-32-2

References:

1. Harper, D.B. and Kennedy, J.T. Purification and properties of S-adenosylmethionine: aldoxime O-methyltransferase from Pseudomonas sp. N.C.I.B. 11652. Biochem. J. 226 (1985) 147-153. [PMID: 3977861]

[EC 2.1.1.91 created 1989]

[EC 2.1.1.92 Deleted entry: bergaptol O-methyltransferase. Now included with EC 2.1.1.69, 5-hydroxyfuranocoumarin 5-O-methyltransferase. The reaction with bergaptol is a specific example of the general reaction associated with EC 2.1.1.69. (EC 2.1.1.92 created 1989, deleted 2006)]

[EC 2.1.1.93 Deleted entry: xanthotoxol O-methyltransferase. Enzyme is identical to EC 2.1.1.70, 8-hydroxyfuranocoumarin 8-O-methyltransferase. (EC 2.1.1.93 created 1989, deleted 2008)]

EC 2.1.1.94

Accepted name: tabersonine 16-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 16-hydroxytabersonine = S-adenosyl-L-homocysteine + 16-methoxytabersonine

For diagram click here.

Other name(s): 11-demethyl-17-deacetylvindoline 11-methyltransferase; 11-O-demethyl-17-O-deacetylvindoline O-methyltransferase; S-adenosyl-L-methionine:11-O-demethyl-17-O-deacetylvindoline 11-O-methyltransferase

Systematic name: S-adenosyl-L-methionine:16-hydroxytabersonine 16-O-methyltransferase

Comments: Involved in the biosynthesis of vindoline from tabersonine in the Madagascar periwinkle, Catharanthus roseus.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 100984-95-0

References:

1. De Luca, V., Balsevich, J., Tyler, R.T., Eilert, U., Panchuk, B.D. and Kurz, W.G.W. Biosynthesis of indole alkaloids - developmental regulation of the biosynthetic-pathway from tabersonine to vindoline in Catharanthus roseus. J. Plant Physiol. 125 (1986) 147-156.

2. Fahn, W., Laussermair, E., Deus-Neumann, B. and Stöckigt, J. Late enzymes of vindoline biosynthesis. S-Adenosyl-L-methionine:11-O-demethyl-17-O-deacetylvindoline 11-O-methylase and unspecific acetylesterase. Plant Cell Rep. 4 (1985) 337-340.

[EC 2.1.1.94 created 1989, modified 2005]

EC 2.1.1.95

Accepted name: tocopherol C-methyltransferase

Reaction: (1) S-adenosyl-L-methionine + γ-tocopherol = S-adenosyl-L-homocysteine + α-tocopherol
(2) S-adenosyl-L-methionine + δ-tocopherol = S-adenosyl-L-homocysteine + β-tocopherol
(3) S-adenosyl-L-methionine + γ-tocotrienol = S-adenosyl-L-homocysteine + α-tocotrienol
(4) S-adenosyl-L-methionine + δ-tocotrienol = S-adenosyl-L-homocysteine + β-tocotrienol

For diagram of reaction, click here or click here

Other name(s): γ-tocopherol methyltransferase; VTE4 (gene name); S-adenosyl-L-methionine:γ-tocopherol 5-O-methyltransferase (incorrect); tocopherol O-methyltransferase (incorrect)

Systematic name: S-adenosyl-L-methionine:γ-tocopherol 5-C-methyltransferase

Comments: The enzymes from plants and photosynthetic bacteria have similar efficiency with the γ and δ isomers of tocopherols and tocotrienols.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 84788-82-9

References:

1. Camara, B. and D'Harlingue, A. Demonstration and solubilization of S-adenosylmethionine: γ-tocopherol methyltransferase from Capsicum chromoplasts. Plant Cell Rep. 4 (1985) 31-32. [PMID: 24253640]

2. Koch, M., Lemke, R., Heise, K.P. and Mock, H.P. Characterization of γ-tocopherol methyltransferases from Capsicum annuum L and Arabidopsis thaliana. Eur. J. Biochem. 270 (2003) 84-92. [PMID: 12492478]

3. Zhang, G.Y., Liu, R.R., Xu, G., Zhang, P., Li, Y., Tang, K.X., Liang, G.H. and Liu, Q.Q. Increased α-tocotrienol content in seeds of transgenic rice overexpressing Arabidopsis γ-tocopherol methyltransferase. Transgenic Res. 22 (2013) 89-99. [PMID: 22763462]

[EC 2.1.1.95 created 1989, modified 2013, modified 2019]

EC 2.1.1.96

Accepted name: thioether S-methyltransferase

Reaction: S-adenosyl-L-methionine + dimethyl sulfide = S-adenosyl-L-homocysteine + trimethylsulfonium

For diagram of reaction click here.

Other name(s): S-adenosyl-L-methionine:thioether S-methyltransferase; thioether methyltransferase

Systematic name: S-adenosyl-L-methionine:dimethyl-sulfide S-methyltransferase

Comments: Also acts on dimethyl selenide, dimethyl telluride, diethyl sulfide, 1,4-dithiane and many other thioethers.

Links to other databases: BRENDA, EXPASY, KEGG, PDB, Metacyc, CAS registry number: 114797-02-3

References:

1. Mozier, N.M., McConnell, P. and Hoffman, J.L. S-Adenosyl-L-methionine:thioether S-methyltransferase, a new enzyme in sulfur and selenium metabolism. J. Biol. Chem. 263 (1988) 4527-4531. [PMID: 3350800]

[EC 2.1.1.96 created 1990]

EC 2.1.1.97

Accepted name: 3-hydroxyanthranilate 4-C-methyltransferase

Reaction: S-adenosyl-L-methionine + 3-hydroxyanthranilate = S-adenosyl-L-homocysteine + 3-hydroxy-4-methylanthranilate

Other name(s): 3-hydroxyanthranilate 4-methyltransferase

Systematic name: S-adenosyl-L-methionine:3-hydroxyanthranilate 4-C-methyltransferase

Comments: Involved in the biosynthesis of the antibiotic actinomycin in Streptomyces antibioticus.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 112445-22-4

References:

1. Fawaz, F. and Jones, G.H. Actinomycin synthesis in Streptomyces antibioticus. Purification and properties of a 3-hydroxyanthranilate 4-methyltransferase. J. Biol. Chem. 263 (1988) 4602-4606. [PMID: 2450873]

[EC 2.1.1.97 created 1990]

EC 2.1.1.98

Accepted name: diphthine synthase

Reaction: 3 S-adenosyl-L-methionine + 2-[(3S)-3-carboxy-3-aminopropyl]-L-histidine-[translation elongation factor 2] = 3 S-adenosyl-L-homocysteine + diphthine-[translation elongation factor 2] (overall reaction)
(1a) S-adenosyl-L-methionine + 2-[(3S)-3-carboxy-3-aminopropyl]-L-histidine-[translation elongation factor 2] = S-adenosyl-L-homocysteine + 2-[(3S)-3-carboxy-3-(methylamino)propyl]-L-histidine-[translation elongation factor 2]
(1b) S-adenosyl-L-methionine + 2-[(3S)-3-carboxy-3-(methylamino)propyl]-L-histidine-[translation elongation factor 2] = S-adenosyl-L-homocysteine + 2-[(3S)-3-carboxy-3-(dimethylamino)propyl]-L-histidine-[translation elongation factor 2]
(1c) S-adenosyl-L-methionine + 2-[(3S)-3-carboxy-3-(dimethylamino)propyl]-L-histidine-[translation elongation factor 2] = S-adenosyl-L-homocysteine + diphthine-[translation elongation factor 2]

For diagram of reaction click here.

Glossary: diphthine = 2-[(3S)-3-carboxy-3-(trimethylamino)propyl]-L-histidine

Other name(s): S-adenosyl-L-methionine:elongation factor 2 methyltransferase (ambiguous); diphthine methyltransferase (ambiguous); S-adenosyl-L-methionine:2-(3-carboxy-3-aminopropyl)-L-histidine-[translation elongation factor 2] methyltransferase; Dph5 (ambiguous)

Systematic name: S-adenosyl-L-methionine:2-[(3S)-3-carboxy-3-aminopropyl]-L-histidine-[translation elongation factor 2] methyltransferase (diphthine-[translation elongation factor 2]-forming)

Comments: This archaeal enzyme produces the trimethylated product diphthine, which is converted into diphthamide by EC 6.3.1.14, diphthine—ammonia ligase. Different from the eukaryotic enzyme, which produces diphthine methyl ester (cf. EC 2.1.1.314). In the archaeon Pyrococcus horikoshii the enzyme acts on His600 of elongation factor 2.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 114514-25-9

References:

1. Zhu, X., Kim, J., Su, X. and Lin, H. Reconstitution of diphthine synthase activity in vitro. Biochemistry 49 (2010) 9649-9657. [PMID: 20873788]

[EC 2.1.1.98 created 1990, modified 2013, modified 2015]

EC 2.1.1.99

Accepted name: 3-hydroxy-16-methoxy-2,3-dihydrotabersonine N-methyltransferase

Reaction: S-adenosyl-L-methionine + 3-hydroxy-16-methoxy-2,3-dihydrotabersonine = S-adenosyl-L-homocysteine + deacetoxyvindoline

For diagram click here.

Other name(s): 16-methoxy-2,3-dihydro-3-hydroxytabersonine methyltransferase; NMT; 16-methoxy-2,3-dihydro-3-hydroxytabersonine N-methyltransferase; S-adenosyl-L-methionine:16-methoxy-2,3-dihydro-3-hydroxytabersonine N-methyltransferase

Systematic name: S-adenosyl-L-methionine:3-hydroxy-16-methoxy-2,3-dihydrotabersonine N-methyltransferase

Comments: Involved in the biosynthesis of vindoline from tabersonine in the Madagascar periwinkle Catharanthus roseus.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 113478-40-3

References:

1. De Luca, V., Balsevich, J., Tyler, R.T., Eilert, U., Panchuk, B.D. and Kurz, W.G.W. Biosynthesis of indole alkaloids - developmental regulation of the biosynthetic-pathway from tabersonine to vindoline in Catharanthus roseus. J. Plant Physiol. 125 (1986) 147-156.

2. De Luca, V. and Cutler, A.J. Subcellular localization of enzymes involved in indole alkaloid biosynthesis in Catharanthus roseus. Plant Physiol. 85 (1987) 1099-1102. [PMID: 16665811]

[EC 2.1.1.99 created 1990, modified 2005]

EC 2.1.1.100

Accepted name: protein-S-isoprenylcysteine O-methyltransferase

Reaction: S-adenosyl-L-methionine + protein C-terminal S-farnesyl-L-cysteine = S-adenosyl-L-homocysteine + protein C-terminal S-farnesyl-L-cysteine methyl ester

Other name(s): farnesyl cysteine C-terminal methyltransferase; farnesyl-protein carboxymethyltransferase; protein C-terminal farnesylcysteine O-methyltransferase; farnesylated protein C-terminal O-methyltransferase; isoprenylated protein methyltransferase; prenylated protein methyltransferase; protein S-farnesylcysteine C-terminal methyltransferase; S-farnesylcysteine methyltransferase; prenylcysteine carboxylmethyltransferase [misleading]; prenylcysteine carboxymethyltransferase [misleading]; prenylcysteine methyltransferase

Systematic name: S-adenosyl-L-methionine:protein-C-terminal-S-farnesyl-L-cysteine O-methyltransferase

Comments: C-terminal S-geranylgeranylcysteine and S-geranylcysteine residues are also methylated, but more slowly.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 130731-20-3

References:

1. Clarke, S., Vogel, J.P., Deschenes, R.J. and Stock, J. Posttranslational modification of the Ha-ras oncogene protein: evidence for a third class of protein carboxyl methyltransferases. Proc. Natl. Acad. Sci. USA 85 (1988) 4643-4647. [PMID: 3290900]

2. Ota, I.M. and Clarke, S. Enzymatic methylation of 23-29-kDa bovine retinal rod outer segment membrane proteins. Evidence for methyl ester formation at carboxyl-terminal cysteinyl residues. J. Biol. Chem. 264 (1989) 12879-12884. [PMID: 2753892]

3. Stephenson, R.C. and Clarke, S. Identification of a C-terminal protein carboxyl methyltransferase in rat liver membranes utilizing a synthetic farnesyl cysteine-containing peptide substrate. J. Biol. Chem. 265 (1990) 16248-16254. [PMID: 2398053]

[EC 2.1.1.100 created 1992 (EC 2.1.1.24 created 1972, modified 1983, modified 1989, part incorporated 1992)]


Continued with EC 2.1.1.101 to EC 2.1.1.150
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