Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB)

Proposed Changes to the Enzyme List

EC1 oxidoreductases

The entries below are proposed additions and amendments to the Enzyme Nomenclature list. They were prepared for the NC-IUBMB by Keith Tipton, Sinéad Boyce, Gerry Moss, Dick Cammack and Hal Dixon, with assistance from Alan Chester, and were put on the web by Gerry Moss. Comments and suggestions on these draft entries should be sent to Professor K.F. Tipton and Dr S. Boyce (Department of Biochemistry, Trinity College Dublin, Dublin 2, Ireland). These entries were made public June 2003 and approved August 2003.

An asterisk before 'EC' indicates that this is an amendment to an existing enzyme rather than a new enzyme entry.


Contents

EC 1.1.1.253 now EC 1.5.1.33
EC 1.1.1.275 (+)-trans-carveol dehydrogenase
EC 1.1.1.276 serine 3-dehydrogenase
EC 1.1.1.277 3β-hydroxy-5β-steroid dehydrogenase
EC 1.1.1.278 3β-hydroxy-5α-steroid dehydrogenase
EC 1.1.3.31 Deleted.
EC 1.2.1.69 fluoroacetaldehyde dehydrogenase
*EC 1.3.1.43 cyclohexadienyl dehydrogenase
EC 1.3.1.74 2-alkenal reductase
EC 1.3.1.75 divinyl chlorophyllide a 8-vinyl-reductase
*EC 1.3.3.3 coproporphyrinogen oxidase
*EC 1.3.3.4 protoporphyrinogen oxidase
EC 1.3.99.21 (R)-benzylsuccinyl-CoA dehydrogenase
*EC 1.4.1.7 serine 2-dehydrogenase
EC 1.4.4.1 now EC 1.21.4.1
EC 1.5.1.33 pteridine reductase
EC 1.5.1.34 6,7-dihydropteridine reductase
EC 1.6.3 With oxygen as acceptor
EC 1.6.3.1 NADPH oxidase
EC 1.6.99.7 now EC 1.5.1.34
EC 1.8.4.10 adenylyl-sulfate reductase (thioredoxin)
EC 1.13.11.50 acetylacetone-cleaving enzyme
EC 1.14.11.21 clavaminate synthase
EC 1.14.13.80 (R)-limonene 6-monooxygenase
EC 1.14.13.81 magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase
*EC 1.14.16.1 phenylalanine 4-monooxygenase
*EC 1.14.16.2 tyrosine 3-monooxygenase
*EC 1.14.16.4 tryptophan 5-monooxygenase
EC 1.14.17.4 aminocyclopropanecarboxylate oxidase
EC 1.16.1.8 [methionine synthase] reductase
EC 1.17.1.2 4-hydroxy-3-methylbut-2-enyl diphosphate reductase
EC 1.17.1.3 leucoanthocyanidin reductase
EC 1.17.4.3 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase
*EC 1.20.4.2 methylarsonate reductase
EC 1.21.4 With a disulfide as acceptor
EC 1.21.4.1 D-proline reductase (dithiol)
EC 1.21.4.2 glycine reductase
EC 1.21.4.3 sarcosine reductase
EC 1.21.4.4 betaine reductase

Entries

[EC 1.1.1.253 Transferred entry: now EC 1.5.1.33 pteridine reductase. (EC 1.1.1.253 created 1999, deleted 2003)]

EC 1.1.1.275

Common name: (+)-trans-carveol dehydrogenase

Reaction: (+)-trans-carveol + NAD+ = (+)-(S)-carvone + NADH + H+

For diagram click here.

Other name(s): carveol dehydrogenase

Systematic name: (+)-trans-carveol:NAD+ oxidoreductase

Comments: NADP+ cannot replace NAD+. Forms part of the monoterpenoid biosynthesis pathway in Carum carvi (caraway) seeds.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Bouwmeester, H.J., Gershenzon, J., Konings, M.C.J.M. and Croteau, R. Biosynthesis of the monoterpenes limonene and carvone in the fruit of caraway. I. Demonstration of enzyme activities and their changes with development. Plant Physiol. 117 (1998) 901-912. [PMID: 9662532]

[EC 1.1.1.275 created 2003]

EC 1.1.1.276

Common name: serine 3-dehydrogenase

Reaction: L-serine + NADP+ = 2-aminomalonate semialdehyde + NADPH + H+

Systematic name: L-serine:NADP+ 3-oxidoreductase

Comments: The product 2-aminomalonate semialdehyde is spontaneously converted into 2-aminoacetaldehyde and CO2. NAD+ cannot replace NADP+.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 9038-55-5

References:

1. Fujisawa, H., Nagata, S., Chowdhury, E.K., Matsumoto, M. and Misono, H. Cloning and sequencing of the serine dehydrogenase gene from Agrobacterium tumefaciens. Biosci. Biotechnol. Biochem. 66 (2002) 1137-1139.

2. Chowdhury, E.K., Higuchi, K., Nagata, S. and Misono, H. A novel NADP+ dependent serine dehydrogenase from Agrobacterium tumefaciens. Biosci. Biotechnol. Biochem. 61 (1997) 152-157.

[EC 1.1.1.276 created 2003]

EC 1.1.1.277

Common name: 3β-hydroxy-5β-steroid dehydrogenase

Reaction: 3β-hydroxy-5β-pregnane-20-one + NADP+ = 5β-pregnan-3,20-dione + NADPH + H+

For diagram click here.

Other name(s): 3β-hydroxysteroid 5β-oxidoreductase; 3β-hydroxysteroid 5β-progesterone oxidoreductase

Systematic name: 3β-hydroxy-5β-steroid:NADP+ 3-oxidoreductase

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Stuhlemmer, U. and Kreis, W. Cardenolide formation and activity of pregnane-modifying enzymes in cell suspension cultures, shoot cultures and leaves of Digitalis lanata. Plant Physiol. Biochem. 34 (1996) 85-91.

2. Seitz, H.U. and Gaertner, D.E. Enzymes in cardenolide-accumulating shoot cultures of Digitalis purpurea. Plant Cell Tissue Organ. Cult. 38 (1994) 337-344.

3. Lindemann, P. and Luckner, M. Biosynthesis of pregnane derivatives in somatic embryos of Digitalis lanata. Phytochemistry 46 (1997) 507-513.

[EC 1.1.1.277 created 2003]

EC 1.1.1.278

Common name: 3β-hydroxy-5α-steroid dehydrogenase

Reaction: 3β-hydroxy-5α-pregnane-20-one + NADP+ = 5α-pregnan-3,20-dione + NADPH + H+

For diagram click here.

Systematic name: 3β-hydroxy-5α-steroid:NADP+ 3-oxidoreductase

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Lindemann, P. and Luckner, M. Biosynthesis of pregnane derivatives in somatic embryos of Digitalis lanata. Phytochemistry 46 (1997) 507-513.

2. Warneck, H.M. and Seitz, H.U. 3β-Hydroxysteroid oxidoreductase in suspension cultures of Digitalis lanata EHRH. Z. Naturforsch. C: Biosci. 45 (1990) 963-972. [PMID: 2291772]

[EC 1.1.1.278 created 2003]

[EC 1.1.3.31 Deleted entry: methanol oxidase. Cannot be distinguished from EC 1.1.3.13, alcohol oxidase. (EC 1.1.3.31 created 1992, deleted 2003)]

EC 1.2.1.69

Common name: fluoroacetaldehyde dehydrogenase

Reaction: fluoroacetaldehyde + NAD+ + H2O = fluoroacetate + NADH + 2 H+

Systematic name: fluoroacetaldehyde:NAD+ oxidoreductase

Comments: The enzyme from Streptomyces cattleya has a high affinity for fluoroacetate and glycolaldehyde but not for acetaldehyde.

References:

1. Murphy, C.D., Moss, S.J. and O'Hagan, D. Isolation of an aldehyde dehydrogenase involved in the oxidation of fluoroacetaldehyde to fluoroacetate in Streptomyces cattleya. Appl. Environ. Microbiol. 67 (2001) 4919-4921. [PMID: 11571203]

2. Murphy, C.D., Schaffrath, C. and O'Hagan, D. Fluorinated natural products: the biosynthesis of fluoroacetate and 4-fluorothreonine in Streptomyces cattleya. Chemosphere 52 (2003) 455-461. [PMID: 12738270]

[EC 1.2.1.69 created 2003]

*EC 1.3.1.43

Common name: cyclohexadienyl dehydrogenase

Reaction: L-arogenate + NAD+ = L-tyrosine + NADH + CO2

For diagram click here.

Other name(s): arogenate dehydrogenase; arogenic dehydrogenase; pretyrosine dehydrogenase

Systematic name: L-arogenate:NAD+ oxidoreductase

Comments: Also acts on prephenate and D-prephenyllactate. cf. EC 1.3.1.12 prephenate dehydrogenase.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 64295-75-6

References:

1. Bonner, C. and Jensen, R. Arogenate dehydrogenase. Methods Enzymol. 142 (1987) 488-494. [PMID: 3600376]

2. Mayer, E., Waldner-Sander, S., Keller, B., Keller, E. and Lingens, F. Purification of arogenate dehydrogenase from Phenylobacterium immobile. FEBS Lett. 179 (1985) 208-212. [PMID: 3967752]

3. Stenmark, S.L., Pierson, D.L., Jensen, R.A. and Glover, G.I. Blue-green bacteria synthesise L-tyrosine by the pretyrosine pathway. Nature (Lond.) 247 (1974) 290-292.

4. Zamir, L.O., Tiberio, R., Devor, K.A., Sauriol, F., Ahmad, S. and Jensen, R.A. Structure of D-prephenyllactate. A carboxycyclohexadienyl metabolite from Neurospora crassa. J. Biol. Chem. 263 (1988) 17284-17290.

[EC 1.3.1.43 created 1989, modified 2003]

EC 1.3.1.74

Common name: 2-alkenal reductase

Reaction: n-alkanal + NAD(P)+ = alk-2-enal + NAD(P)H + H+

Other name(s): NAD(P)H-dependent alkenal/one oxidoreductase; NADPH:2-alkenal α,β-hydrogenase

Systematic name: n-alkanal:NAD(P)+ 2-oxidoreductase

Comments: Highly specific for 4-hydroxynon-2-enal and non-2-enal. 2-Alkenals of shorter chain have lower affinities. Exhibits high activities also for 2-alkenones such as but-3-en-2-one and pent-3-en-2-one. Inactive with cyclohex-2-en-1-one and 12-oxophytodienoic acid. Involved in the detoxication of α,β-unsaturated aldehydes and ketones.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 162731-81-9

References:

1. Mano, J., Torii, Y., Hayashi, S., Takimoto, K., Matsui, K., Nakamura, K., Inzé, D., Babiychuk, E., Kushnir, S. and Asada, K. The NADPH:quinone oxidoreductase P1-ζ-crystallin in Arabidopsis catalyzes the α,β-hydrogenation of 2-alkenals: detoxication of the lipid peroxide-derived reactive aldehydes. Plant Cell Physiol. 43 (2002) 1445-1455. [PMID: 12514241]

2. Dick, R.A., Kwak, M.K., Sutter, T.R. and Kensler, T.W. Antioxidative function and substrate specificity of NAD(P)H-dependent alkenal/one oxidoreductase. A new role for leukotriene B4 12-hydroxydehydrogenase/15-oxoprostaglandin 13-reductase. J. Biol. Chem. 276 (2001) 40803-40810. [PMID: 11524419]

[EC 1.3.1.74 created 2003]

EC 1.3.1.75

Common name: divinyl chlorophyllide a 8-vinyl-reductase

Reaction: chlorophyllide a + NADP+ = divinyl chlorophyllide a + NADPH + H+

For diagram click here.

Other name(s): [4-vinyl]chlorophyllide a reductase; 4VCR

Systematic name: chlorophyllide-a:NADP+ oxidoreductase

Comments: Also reduces divinyl protochlorophyllide to protochlorophyllide in some species, providing an alternative pathway.

References:

1. Tripathy, B.C., and Rebeiz, C.A. Chloroplast biogenesis 60. Conversion of divinyl protochlorophyllide to monovinyl protochlorophyllide in green(ing) barley, a dark monovinyl/light divinyl plant species.Plant Physiol. 87 (1988) 89-94.

2. Parham, R. and Rebeiz, C.A. Chloroplast biogenesis: [4-vinyl] chlorophyllide a reductase is a divinyl chlorophyllide a-specific, NADPH-dependent enzyme. Biochemistry 31 (1992) 8460-8464. [PMID: 1390630]

3. Parham. R. and Rebeiz, C.A. Chloroplast biogenesis 72: a [4-vinyl]chlorophyllide a reductase assay using divinyl chlorophyllide a as an exogenous substrate. Anal. Biochem. 231 (1995) 164-169. [PMID: 8678296]

4. Kolossov, V.L. and Rebeiz, C.A. Chloroplast biogenesis 84: solubilization and partial purification of membrane-bound [4-vinyl]chlorophyllide a reductase from etiolated barley leaves. Anal. Biochem. 295 (2001) 214-219. [PMID: 11488624]

[EC 1.3.1.75 created 2003]

*EC 1.3.3.3

Common name: coproporphyrinogen oxidase

Reaction: coproporphyrinogen-III + O2 + 2 H+ = protoporphyrinogen-IX + 2 CO2 + 2 H2O

For diagram click here.

Other name(s): coproporphyrinogen III oxidase; coproporphyrinogenase

Systematic name: coproporphyrinogen:oxygen oxidoreductase (decarboxylating)

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 9076-84-0

References:

1. Battle, A.M., Benson, A. and Rimington, C. Purification and properties of coproporphyrinogenase. Biochem. J. 97 (1965) 731-740. [PMID: 5881662]

2. Medlock, A.E. and Dailey, H.A. Human coproporphyrinogen oxidase is not a metalloprotein. J. Biol. Chem. 271 (1996) 32507-32510. [PMID: 8955072]

3. Kohno, H., Furukawa, T., Yoshinaga, T., Tokunaga, R. and Taketani, S. Coproporphyrinogen oxidase. Purification, molecular cloning, and induction of mRNA during erythroid differentiation. J. Biol. Chem. 268 (1993) 21359-21363. [PMID: 8407975]

[EC 1.3.3.3 created 1972, modified 2003]

*EC 1.3.3.4

Common name: protoporphyrinogen oxidase

Reaction: protoporphyrinogen-IX + 1.5 O2 = protoporphyrin-IX + 3 H2O

For diagram click here.

Other name(s): protoporphyrinogen IX oxidase; protoporphyrinogenase

Systematic name: protoporphyrinogen-IX:oxygen oxidoreductase

Comments: Also slowly oxidizes mesoporphyrinogen-IX.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 53986-32-6

References:

1. Poulson, R. The enzymic conversion of protoporphyrinogen IX to protoporphyrin IX in mammalian mitochondria. J. Biol. Chem. 251 (1976) 3730-3733. [PMID: 6461]

2. Poulson, R. and Polglase, W.J. The enzymic conversion of protoporphyrinogen IX to protoporphyrin IX. Protoporphyrinogen oxidase activity in mitochondrial extracts of Saccharomyces cerevisiae. J. Biol. Chem. 250 (1975) 1269-1274. [PMID: 234450]

3. Dailey, H.A. and Dailey, T.A. Protoporphyrinogen oxidase of Myxococcus xanthus. Expression, purification, and characterization of the cloned enzyme. J. Biol. Chem. 271 (1996) 8714-8718. [PMID: 8621504]

4. Wang, K.F., Dailey, T.A. and Dailey, H.A. Expression and characterization of the terminal heme synthetic enzymes from the hyperthermophile Aquifex aeolicus. FEMS Microbiol. Lett. 202 (2001) 115-119. [PMID: 11506917]

5. Corrigall, A.V., Siziba, K.B., Maneli, M.H., Shephard, E.G., Ziman, M., Dailey, T.A., Dailey, H.A., Kirsch. R.E. and Meissner, P.N. Purification of and kinetic studies on a cloned protoporphyrinogen oxidase from the aerobic bacterium Bacillus subtilis. Arch. Biochem. Biophys. 358 (1998) 251-256. [PMID: 9784236]

[EC 1.3.3.4 created 1978, modified 2003]

EC 1.3.99.21

Common name: (R)-benzylsuccinyl-CoA dehydrogenase

Reaction: (R)-2-benzylsuccinyl-CoA + 2 electron-transferring flavoprotein = (E)-2-benzylidenesuccinyl-CoA + 2 reduced electron-transferring flavoprotein

For diagram click here.

Other name(s): BbsG

Systematic name: (R)-benzylsuccinyl-CoA:(acceptor) oxidoreductase

Comments: Requires FAD as cofactor. The enzyme is highly specific for (R)-benzylsuccinyl-CoA and is inhibited by (S)-benzylsuccinyl-CoA. Forms the third step in the anaerobic toluene metabolic pathway in Thauera aromatica. Uses the ferricenium ion as the preferred artificial electron acceptor. Unlike other acyl-CoA dehydrogenases, this enzyme exhibits high substrate- and enantiomer specificity.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Leutwein, C. and Heider, J. (R)-Benzylsuccinyl-CoA dehydrogenase of Thauera aromatica, an enzyme of the anaerobic toluene catabolic pathway. Arch. Microbiol. 178 (2002) 517-524. [PMID: 12420174]

[EC 1.3.99.21 created 2003]

*EC 1.4.1.7

Common name: serine 2-dehydrogenase

Reaction: L-serine + H2O + NAD+ = 3-hydroxypyruvate + NH3 + NADH + H+

Other name(s): L-serine:NAD oxidoreductase (deaminating); serine dehydrogenase

Systematic name: L-serine:NAD+ 2-oxidoreductase (deaminating)

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Kretovich, V.L. and Stepanovich, K.M. [The enzyme catalyzing the reductive amination of oxypyruvate.] (in Russian) Izv. Akad. Nauk SSSR Ser. Biol. No. 2 (1966) 295-300. [PMID: 5972761]

[EC 1.4.1.7 created 1972, modified 2003]

[EC 1.4.4.1 Transferred entry: now EC 1.21.4.1, D-proline reductase (dithiol) (EC 1.4.4.1 created 1972, modified 1982 (EC 1.4.1.6 created 1961, incorporated 1982), deleted 2003)]

EC 1.5.1.33

Common name: pteridine reductase

Reaction: 5,6,7,8-tetrahydrobiopterin + 2 NADP+ = biopterin + 2 NADPH + 2 H+

Other name(s): PTR1; pteridine reductase 1

Systematic name: 5,6,7,8-tetrahydrobiopterin:NADP+ oxidoreductase

Comments: The enzyme from Leishmania (both amastigote and promastigote forms) catalyses the reduction by NADPH of folate and a wide variety of unconjugated pterins, including biopterin, to their tetrahydro forms. It also catalyses the reduction of 7,8-dihydropterins and 7,8-dihydrofolate to their tetrahydro forms. In contrast to EC 1.5.1.3 (dihydrofolate reductase) and EC 1.5.1.34 (6,7-dihydropteridine reductase), pteridine reductase will not catalyse the reduction of the quinonoid form of dihydrobiopterin. The enzyme is specific for NADPH; no activity has been detected with NADH. It also differs from EC 1.5.1.3 in being specific for the B side of NADPH.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 131384-61-7

References:

1. Nare, B., Hardy, L. and Beverley, S.M. The roles of pteridine reductase 1 and dihydrofolate reductase-thymidylate synthase in pteridine metabolism in the protozoan parasite Leishmania major. J. Biol. Chem. 272 (1997) 13883-13891. [PMID: 9153248]

2. Gourley, D.G., Schüttelkopf, A.W., Leonard, G.A., Luba, J., Hardy, L.W., Beverley, S.M. and Hunter, W.N. Pteridine reductase mechanism correlates pterin metabolism with drug resistance in trypanosomatid parasites. Nat. Struct. Biol. 8 (2001) 521-525. [PMID: 11373620]

3. Fitzpatrick, P.F. The aromatic amino acid hydroxylases. Adv. Enzymol. Relat. Areas Mol. Biol. 74 (2000) 235-294. [PMID: 10800597]

[EC 1.5.1.33 created 1999 as EC 1.1.1.253, transfered 2003 to EC 1.5.1.33]

EC 1.5.1.34

Common name: 6,7-dihydropteridine reductase

Reaction: a 5,6,7,8-tetrahydropteridine + NAD(P)H+ = a 6,7-dihydropteridine + NAD(P)H + H+

Other name(s): 6,7-dihydropteridine:NAD(P)H oxidoreductase; DHPR; NAD(P)H2:6,7-dihydropteridine oxidoreductase; NADH-dihydropteridine reductase; NADPH-dihydropteridine reductase; NADPH-specific dihydropteridine reductase; dihydropteridine (reduced nicotinamide adenine dinucleotide) reductase; dihydropteridine reductase; dihydropteridine reductase (NADH)

Systematic name: 5,6,7,8-tetrahydropteridine:NAD(P)H+ oxidoreductase

Comments: The substrate is the quinonoid form of dihydropteridine. Not identical with EC 1.5.1.3 dihydrofolate reductase.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 9074-11-7

References:

1. Harano, T. New diaphorases from Bombyx silkworm eggs. NADH/NADPH cytochrome c reductase activity mediated with 6,7-dimethyltetrahydropterin. Insect Biochem. 2 (1972) 385-399.

2. Hasegawa, H. Dihydropteridine reductase from bovine liver. Purification, crystallization, and isolation of a binary complex with NADH. J. Biochem. (Tokyo) 81 (1977) 169-177. [PMID: 191436]

3. Kaufman, S. Phenylalanine hydroxylase. Methods Enzymol. 5 (1962) 809-816.

4. Lind, K.E. Dihydropteridine reductase. Investigation of the specificity for quinoid dihydropteridine and the inhibition by 2,4-diaminopteridines. Eur. J. Biochem. 25 (1972) 560-562. [PMID: 4402916]

5. Nakanishi, N., Hasegawa, H. and Watabe, S. A new enzyme, NADPH-dihydropteridine reductase in bovine liver. J. Biochem. (Tokyo) 81 (1977) 681-685. [PMID: 16875]

[EC 1.5.1.34 created 1972 as EC 1.6.99.7, modified 1981 (EC 1.6.99.10 created 1978, incorporated 1981), transferred 2003 to EC 1.5.1.34]

EC 1.6.3 With oxygen as acceptor

EC 1.6.3.1

Common name: NADPH oxidase

Reaction: NAD(P)H + H+ + O2 = NAD(P)+ + H2O2

Other name(s): THOX2; ThOX; dual oxidase; p138tox; thyroid NADPH oxidase; thyroid oxidase; thyroid oxidase 2

Systematic name: NAD(P)H:oxygen oxidoreductase

Comments: Requires FAD, heme and calcium. When calcium is present, this transmembrane glycoprotein generates H2O2 by transfering electrons from intracellular NAD(P)H to extracellular molecular oxygen. The electron bridge within the enzyme contains one molecule of FAD and probably two heme groups. This flavoprotein is expressed at the apical membrane of thyrocytes, and provides H2O2 for the thyroid peroxidase-catalysed biosynthesis of thyroid hormones.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Moreno, J.C., Bikker, H., Kempers, M.J., van Trotsenburg, A.S., Baas, F., de Vijlder, J.J., Vulsma, T. and Ris-Stalpers, C. Inactivating mutations in the gene for thyroid oxidase 2 (THOX2) and congenital hypothyroidism. N. Engl. J. Med. 347 (2002) 95-102. [PMID: 12110737]

2. De Deken, X., Wang, D., Dumont, J.E. and Miot, F. Characterization of ThOX proteins as components of the thyroid H2O2-generating system. Exp. Cell Res. 273 (2002) 187-196. [PMID: 11822874]

3. De Deken, X., Wang, D., Many, M.C., Costagliola, S., Libert, F., Vassart, G., Dumont, J.E. and Miot, F. Cloning of two human thyroid cDNAs encoding new members of the NADPH oxidase family. J. Biol. Chem. 275 (2000) 23227-23233. [PMID: 10806195]

4. Dupuy, C., Ohayon, R., Valent, A., Noel-Hudson, M.S., Deme, D. and Virion, A Purification of a novel flavoprotein involved in the thyroid NADPH oxidase. Cloning of the porcine and human cDNAs. J. Biol. Chem. 274 (1999) 37265-37269. [PMID: 10601291]

5. Leseney, A.M., Deme, D., Legue, O., Ohayon, R., Chanson, P., Sales, J.P., Pires de Carvalho, D., Dupuy, C. and Virion, A. Biochemical characterization of a Ca2+/NAD(P)H-dependent H2O2 generator in human thyroid tissue. Biochimie 81 (1999) 373-380. [PMID: 10401672]

6. Dupuy, C., Virion, A., Ohayon, R., Kaniewski, J., Deme, D. and Pommier, J. Mechanism of hydrogen peroxide formation catalyzed by NADPH oxidase in thyroid plasma membrane. J. Biol. Chem. 266 (1991) 3739-3743. [PMID: 1995628]

[EC 1.6.3.1 created 2003]

[EC 1.6.99.7 Transferred entry: now EC 1.5.1.34 6,7-dihydropteridine reductase. (EC 1.6.99.7 created 1972, modified 1981 (EC 1.6.99.10 created 1978, incorporated 1981), deleted 2003)]

EC 1.8.4.10

Common name: adenylyl-sulfate reductase (thioredoxin)

Reaction: AMP + sulfite + thioredoxin disulfide = 5'-adenylyl sulfate + thioredoxin

Other name(s): thioredoxin-dependent 5'-adenylylsulfate reductase

Systematic name: AMP,sulfite:thioredoxin-disulfide oxidoreductase (adenosine-5'-phosphosulfate-forming)

Comments: Uses adenylyl sulfate, not phosphoadenylyl sulfate, distinguishing this enzyme from EC 1.8.4.8, phosphoadenylyl-sulfate reductase (thioredoxin). Uses thioredoxin as electron donor, not glutathione or other donors, distinguishing it from EC 1.8.4.9 [adenylyl-sulfate reductase (glutathione)] and EC 1.8.99.2 (adenylyl-sulfate reductase).

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Bick, J.A., Dennis, J.J., Zylstra, G.J., Nowack, J. and Leustek, T. Identification of a new class of 5-adenylylsulfate (APS) reductase from sulfate-assimilating bacteria. J. Bacteriol. 182 (2000) 135-142. [PMID: 10613872]

2. Abola, A.P., Willits, M.G., Wang, R.C. and Long, S.R. Reduction of adenosine-5'-phosphosulfate instead of 3'-phosphoadenosine-5'-phosphosulfate in cysteine biosynthesis by Rhizobium meliloti and other members of the family Rhizobiaceae. J. Bacteriol. 181 (1999) 5280-5287. [PMID: 10464198]

3. Williams, S.J., Senaratne, R.H., Mougous, J.D., Riley, L.W. and Bertozzi, C.R. 5'-Adenosinephosphosulfate lies at a metabolic branchpoint in mycobacteria. J. Biol. Chem. 277 (2002) 32606-32615. [PMID: 12072441]

4. Neumann, S., Wynen, A., Trüper, H.G. and Dahl, C. Characterization of the cys gene locus from Allochromatium vinosum indicates an unusual sulfate assimilation pathway. Mol. Biol. Rep. 27 (2000) 27-33. [PMID: 10939523]

[EC 1.8.4.10 created 2003]

EC 1.13.11.50

Common name: acetylacetone-cleaving enzyme

Reaction: pentane-2,4-dione + O2 = acetate + 2-oxopropanal

Other name(s): Dke1; acetylacetone dioxygenase; diketone cleaving dioxygenase; diketone cleaving enzyme

Systematic name: acetylacetone:oxygen oxidoreductase

Comments: An Fe(II)-dependent enzyme. Forms the first step in the acetylacetone degradation pathway of Acinetobacter johnsonii. While acetylacetone is by far the best substrate, heptane-3,5-dione, octane-2,4-dione, 2-acetylcyclohexanone and ethyl acetoacetate can also act as substrates.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Straganz, G.D., Glieder, A., Brecker, L., Ribbons, D.W. and Steiner, W. Acetylacetone-cleaving enzyme Dke1: a novel C-C-bond-cleaving enzyme from Acinetobacter johnsonii. Biochem. J. 369 (2003) 573-581. [PMID: 12379146]

[EC 1.13.11.50 created 2003]

EC 1.14.11.21

Common name: clavaminate synthase

Reaction: (1) deoxyamidinoproclavaminate + 2-oxoglutarate + O2 = amidinoproclavaminate + succinate + CO2 + H2O

(2) proclavaminate + 2-oxoglutarate + O2 = dihydroclavaminate + CO2 + 2 H2O

(3) dihydroclavaminate + 2-oxoglutarate + O2 = clavaminate + CO2 + 2 H2O

For diagram click here.

Other name(s): clavaminate synthase 2; clavaminic acid synthase

Systematic name: deoxyamidinoproclavaminate,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating)

Comments: Contains nonheme iron. Catalyses three separate oxidative reactions in the pathway for the biosythesis of the β-lactamase inhibitor clavulanate in Streptomyces clavuligerus. The first step (hydroxylation) is separated from the latter two (oxidative cyclization and desaturation) by the action of EC 3.5.3.22, proclavaminate amidinohydrolase. The three reactions are all catalysed at the same nonheme iron site.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Salowe, S.P., Krol, W.J., Iwatareuyl, D. and Townsend, C.A. Elucidation of the order of oxidations and identification of an intermediate in the multistep clavaminate synthase reaction. Biochemistry 30 (1991) 2281-2292. [PMID: 1998687]

2. Zhou, J., Gunsior, M., Bachmann, B.O., Townsend, C.A. and Solomon, E.I. Substrate binding to the α-ketoglutarate-dependent non-heme iron enzyme clavaminate synthase 2: Coupling mechanism of oxidative decarboxylation and hydroxylation. J. Am. Chem. Soc. 120 (1998) 13539-13540.

3. Zhang, Z.H., Ren, J.S., Stammers, D.K., Baldwin, J.E., Harlos, K. and Schofield, C.J. Structural origins of the selectivity of the trifunctional oxygenase clavaminic acid synthase. Nat. Struct. Biol. 7 (2000) 127-133. [PMID: 10655615]

4. Zhou, J., Kelly, W.L., Bachmann, B.O., Gunsior, M., Townsend, C.A. and Solomon, E.I. Spectroscopic studies of substrate interactions with clavaminate synthase 2, a multifunctional α-KG-dependent non-heme iron enzyme: Correlation with mechanisms and reactivities. J. Am. Chem. Soc. 123 (2001) 7388-7398.

5. Townsend, C.A. New reactions in clavulanic acid biosynthesis. Curr. Opin. Chem. Biol. 6 (2002) 583-589. [PMID: 12413541]

[EC 1.14.11.21 created 2003]

EC 1.14.13.80

Common name: (R)-limonene 6-monooxygenase

Reaction: (+)-(R)-limonene + NADPH + H+ + O2 = (+)-trans-carveol + NADP+ + H2O

For diagram click here.

Other name(s): (+)-limonene-6-hydroxylase; (+)-limonene 6-monooxygenase

Systematic name: (R)-limonene,NADPH:oxygen oxidoreductase (6-hydroxylating)

Comments: The reaction is stereospecific with over 95% yield of (+)-trans-carveol from (R)-limonene. (S)-Limonene, the substrate for EC 1.14.13.48, (S)-limonene 6-monooxygenase, is not a substrate. Forms part of the carvone biosynthesis pathway in Carum carvi (caraway) seeds.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 221461-49-0

References:

1. Bouwmeester, H.J., Gershenzon, J., Konings, M.C.J.M. and Croteau, R. Biosynthesis of the monoterpenes limonene and carvone in the fruit of caraway. I. Demonstration of enzyme activities and their changes with development. Plant Physiol. 117 (1998) 901-912. [PMID: 9662532]

2. Bouwmeester, H.J., Konings, M.C.J.M., Gershenzon, J., Karp, F. and Croteau, R. Cytochrome P-450 dependent (+)-limonene-6-hydroxylation in fruits of caraway (Carum Carvi). Phytochemistry 50 (1999) 243-248.

[EC 1.14.13.80 created 2003]

EC 1.14.13.81

Common name: magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase

Reaction: (1) magnesium-protoporphyrin IX 13-monomethyl ester + NADPH + H+ + O2 = 131-hydroxy-magnesium-protoporphyrin IX 13-monomethyl ester + NADP+ + H2O

(2) 131-hydroxy-magnesium-protoporphyrin IX 13-monomethyl ester + NADPH + H+ + O2 = 131-oxo-magnesium-protoporphyrin IX 13-monomethyl ester + NADP+ + 2 H2O

(3) 131-oxo-magnesium-protoporphyrin IX 13-monomethyl ester + NADPH + H+ + O2 = divinylprotochlorophyllide + NADP+ + 2 H2O

For diagram of reaction click here (chlorophyll biosynthesis).

Other name(s): Mg-protoporphyrin IX monomethyl ester (oxidative) cyclase

Systematic name: magnesium-protoporphyrin-IX 13-monomethyl ester,NADPH:oxygen oxidoreductase (hydroxylating)

Comments: Requires Fe(II) for activity. The cyclase activity in Chlamydomonas reinhardtii is associated exclusively with the membranes, whereas that from cucumber cotyledons requires both membrane and soluble fractions for activity.

References:

1. Bollivar, D.W. and Beale, S.I. The chlorophyll biosynthetic enzyme Mg-protoporphyrin IX monomethyl ester (oxidative) cyclase (characterization and partial purification from Chlamydomonas reinhardtii and Synechocystis sp. PCC 6803). Plant Physiol. 112 (1996) 105-114. [PMID: 12226378]

[EC 1.14.13.81 created 2003]

*EC 1.14.16.1

Common name: phenylalanine 4-monooxygenase

Reaction: L-phenylalanine + tetrahydrobiopterin + O2 = L-tyrosine + 4a-hydroxytetrahydrobiopterin

Other name(s): phenylalaninase; phenylalanine 4-hydroxylase; phenylalanine hydroxylase

Systematic name: L-phenylalanine,tetrahydrobiopterin:oxygen oxidoreductase (4-hydroxylating)

Comments: The active centre contains mononuclear iron(II). The reaction involves an arene oxide that rearranges to give the phenolic hydroxy group. This results in the hydrogen at C-4 migrating to C-3 and in part being retained. This process is known as the NIH-shift. The 4a-hydroxytetrahydrobiopterin formed can dehydrate to 6,7-dihydrobiopterin, both spontaneously and by the action of EC 4.2.1.96, 4a-hydroxytetrahydrobiopterin dehydratase. The 6,7-dihydrobiopterin can be enzymically reduced back to tetrahydrobiopterin, by EC 1.5.1.34, 6,7-dihydropteridine reductase, or slowly rearranges into the more stable compound 7,8-dihydrobiopterin.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 9029-73-6

References:

1. Guroff, G. and Rhoads, C.A. Phenylalanine hydroxylation by Pseudomonas species (ATCC 11299a). Nature of the cofactor. J. Biol. Chem. 244 (1969) 142-146. [PMID: 5773277]

2. Kaufman, S. Studies on the mechanism of the enzymic conversion of phenylalanine to tyrosine. J. Biol. Chem. 234 (1959) 2677-2682.

3. Mitoma, C. Studies on partially purified phenylalanine hydroxylase. Arch. Biochem. Biophys. 60 (1956) 476-484.

4. Udenfriend, S. and Cooper, J.R. The enzymic conversion of phenylalanine to tyrosine. J. Biol. Chem. 194 (1952) 503-511.

5. Carr, R.T., Balasubramanian, S., Hawkins, P.C. and Benkovic, S.J. Mechanism of metal-independent hydroxylation by Chromobacterium violaceum phenylalanine hydroxylase. Biochemistry 34 (1995) 7525-7532. [PMID: 7779797]

6. Andersen, O.A., Flatmark, T. and Hough, E. High resolution crystal structures of the catalytic domain of human phenylalanine hydroxylase in its catalytically active Fe(II) form and binary complex with tetrahydrobiopterin. J. Mol. Biol. 314 (2001) 266-278. [PMID: 11718561]

7. Erlandsen, H., Kim, J.Y., Patch, M.G., Han, A., Volner, A., Abu-Omar, M.M. and Stevens, R.C. Structural comparison of bacterial and human iron-dependent phenylalanine hydroxylases: similar fold, different stability and reaction rates. J. Mol. Biol. 320 (2002) 645-661. [PMID: 12096915]

[EC 1.14.16.1 created 1961 as EC 1.99.1.2, transferred 1965 to EC 1.14.3.1, transferred 1972 to EC 1.14.16.1, modified 2002, modified 2003]

*EC 1.14.16.2

Common name: tyrosine 3-monooxygenase

Reaction: L-tyrosine + tetrahydrobiopterin + O2 = 3,4-dihydroxy-L-phenylalanine + 4a-hydroxytetrahydrobiopterin

Other name(s): L-tyrosine hydroxylase; tyrosine 3-hydroxylase; tyrosine hydroxylase

Systematic name: L-tyrosine,tetrahydrobiopterin:oxygen oxidoreductase (3-hydroxylating)

Comments: The active centre contains mononuclear iron(II). The enzyme is activated by phosphorylation, catalysed by EC 2.7.1.128, [aceteyl-CoA caboxylase]kinase. The 4a-hydroxytetrahydrobiopterin formed can dehydrate to 6,7-dihydrobiopterin, both spontaneously and by the action of EC 4.2.1.96, 4a-hydroxytetrahydrobiopterin dehydratase. The 6,7-dihydrobiopterin can be enzymically reduced back to tetrahydrobiopterin, by EC 1.5.1.34 (6,7-dihydropteridine reductase), or slowly rearranges into the more stable compound 7,8-dihydrobiopterin.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 9036-22-0

References:

1. El Mestikawy, S., Glowinski, J. and Hamon, M. Tyrosine hydroxylase activation in depolarized dopaminergic terminals -involvement of Ca2+-dependent phosphorylation. Nature (Lond.) 302 (1983) 830-832. [PMID: 6133218]

2. Ikeda, M., Levitt, M. and Udenfriend, S. Phenylalanine as substrate and inhibitor of tyrosine hydroxylase. Arch. Biochem. Biophys. 120 (1967) 420-427. [PMID: 6033458]

3. Nagatsu, T., Levitt, M. and Udenfriend, S. Tyrosine hydroxylase. The initial step in norepinephrine biosynthesis. J. Biol. Chem. 239 (1964) 2910-2917.

4. Pigeon, D., Drissi-Daoudi, R., Gros, F. and Thibault, J. Copurification of tyrosine-hydroxylase from rat pheochromocytoma, with a protein-kinase activity. C.R. Acad. Sci. Paris, Ser. 3, 302 (1986) 435-438. [PMID: 2872947]

5. Goodwill, K.E., Sabatier, C., Marks, C., Raag, R., Fitzpatrick, P.F. and Stevens, R.C. Crystal structure of tyrosine hydroxylase at 2.3 Å and its implications for inherited neurodegenerative diseases. Nat. Struct. Biol. 4 (1997) 578-585. [PMID: 9228951]

[EC 1.14.16.2 created 1972, modified 2003]

*EC 1.14.16.4

Common name: tryptophan 5-monooxygenase

Reaction: L-tryptophan + tetrahydrobiopterin + O2 = 5-hydroxy-L-tryptophan + 4a-hydroxytetrahydrobiopterin

Other name(s): L-tryptophan hydroxylase; indoleacetic acid-5-hydroxylase; tryptophan 5-hydroxylase; tryptophan hydroxylase

Systematic name: L-tryptophan,tetrahydrobiopterin:oxygen oxidoreductase (5-hydroxylating)

Comments: The active centre contains mononuclear iron(II). The enzyme is activated by phosphorylation, catalysed by a Ca2+-activated protein kinase. The 4a-hydroxytetrahydrobiopterin formed can dehydrate to 6,7-dihydrobiopterin, both spontaneously and by the action of EC 4.2.1.96, 4a-hydroxytetrahydrobiopterin dehydratase. The 6,7-dihydrobiopterin can be enzymically reduced back to tetrahydrobiopterin, by EC 1.5.1.34 (6,7-dihydropteridine reductase), or slowly rearranges into the more stable compound 7,8-dihydrobiopterin.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 9037-21-2

References:

1. Friedman, P.A., Kappelman, A.H. and Kaufman, S. Partial purification and characterization of tryptophan hydroxylase from rabbit hindbrain. J. Biol. Chem. 247 (1972) 4165-4173. [PMID: 4402511]

2. Hamon, M., Bourgoin, S., Artaud, F. and Glowinski, J. The role of intraneuronal 5-HT and of tryptophan hydroxylase activation in the control of 5-HT synthesis in rat brain slices incubated in K+-enriched medium. J. Neurochem. 33 (1979) 1031-1042. [PMID: 315449]

3. Ichiyama, A., Nakamura, S., Nishizuka, Y. and Hayaishi, O. Enzymic studies on the biosynthesis of serotonin in mammalian brain. J. Biol. Chem. 245 (1970) 1699-1709. [PMID: 5309585]

4. Jequier, E., Robinson, B.S., Lovenberg, W. and Sjoerdsma, A. Further studies on tryptophan hydroxylase in rat brainstem and beef pineal. Biochem. Pharmacol. 18 (1969) 1071-1081. [PMID: 5789774]

5. Wang, L., Erlandsen, H., Haavik, J., Knappskog, P.M. and Stevens, R.C. Three-dimensional structure of human tryptophan hydroxylase and its implications for the biosynthesis of the neurotransmitters serotonin and melatonin. Biochemistry 41 (2002) 12569-12574. [PMID: 12379098]

[EC 1.14.16.4 created 1972, modified 2003]

EC 1.14.17.4

Common name: aminocyclopropanecarboxylate oxidase

Reaction: 1-aminocyclopropane-1-carboxylate + ascorbate + O2 = ethylene + cyanide + dehydroascorbate + CO2 + 2 H2O

For diagram click here.

Other name(s): ACC oxidase; ethylene-forming enzyme

Systematic name: 1-aminocyclopropane-1-carboxylate oxygenase (ethylene-forming)

Comments: A nonheme iron enzyme. Requires CO2 for activity. In the enzyme from plants, the ethylene has signalling functions such as stimulation of fruit-ripening.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Zhang, Z.H., Schofield, C.J., Baldwin, J.E., Thomas, P. and John, P. Expression, purification and characterization of 1-aminocyclopropane-1-carboxylate oxidase from tomato in Escherichia coli. Biochem. J. 307 (1995) 77-85. [PMID: 7717997]

2. Zhang, Z.H., Barlow, J.N., Baldwin, J.E. and Schofield, C.J. Metal-catalyzed oxidation and mutagenesis studies on the iron(II) binding site of 1-aminocyclopropane-1-carboxylate oxidase. Biochemistry 36 (1997) 15999-16007. [PMID: 9398335]

3. Pirrung, M.C. Ethylene biosynthesis from 1-aminocyclopropanecarboxylic acid. Acc. Chem. Res. 32 (1999) 711-718.

4. Charng, Y., Chou, S.J., Jiaang, W.T., Chen, S.T. and Yang, S.F. The catalytic mechanism of 1-aminocyclopropane-1-carboxylic acid oxidase. Arch. Biochem. Biophys. 385 (2001) 179-185. [PMID: 11361015]

5. Thrower, J.S., Blalock, R. and Klinman, J.P. Steady-state kinetics of substrate binding and iron release in tomato ACC oxidase. Biochemistry 40 (2001) 9717-9724. [PMID: 11583172]

[EC 1.14.17.4 created 2003]

EC 1.16.1.8

Common name: [methionine synthase] reductase

Reaction: 2 [methionine synthase]-methylcob(I)alamin + 2 S-adenosylhomocysteine + NADP+ = 2 [methionine synthase]-cob(I)alamin + NADPH + H+ + 2 S-adenosylLmethionine

For diagram of reaction click here

Other name(s): methionine synthase cob(II)alamin reductase (methylating); methionine synthase reductase; [methionine synthase]-cobalamin methyltransferase (cob(II)alamin reducing); methionine synthase cob(II)alamin reductase (methylating); methionine synthase reductase

Systematic name: [methionine synthase]-methylcob(I)alamin,S-adenosylhomocysteine:NADP+ oxidoreductase

Comments: In humans, the enzyme is a flavoprotein containing FAD and FMN. The substrate of the enzyme is the inactivated [Co(II)] form of EC 2.1.1.13, methionine synthase. Electrons are transferred from NADPH to FAD to FMN. Defects in this enzyme lead to hereditary hyperhomocysteinemia.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 207004-87-3

References:

1. Leclerc, D., Wilson, A., Dumas, R., Gafuik, C., Song, D., Watkins, D., Heng, H.H.Q., Rommens, J.M., Scherer, S.W., Rosenblatt, D.S., Gravel, R.A. Cloning and mapping of a cDNA for methionine synthase reductase, a flavoprotein defective in patients with homocystinuria. Proc. Natl. Acad. Sci. USA, 95 (1998) 3059-3064. [PMID: 9501215]

2. Olteanu, H. and Banerjee, R. Human methionine synthase reductase, a soluble P-450 reductase-like dual flavoprotein, is sufficient for NADPH-dependent methionine synthase activation. J. Biol. Chem. 276 (2001) 35558-35563. [PMID: 11466310]

3. Olteanu, H., Munson, T. and Banerjee, R. Differences in the efficiency of reductive activation of methionine synthase and exogenous electron acceptors between the common polymorphic variants of human methionine synthase reductase. Biochemistry 41 (2002) 13378-13385. [PMID: 12416982]

[EC 1.16.1.8 created 1999 as EC 2.1.1.135, transferred 2003 to EC 1.16.1.8]

EC 1.17.1.2

Common name: 4-hydroxy-3-methylbut-2-enyl diphosphate reductase

Reaction: isopentenyl diphosphate + NAD(P)+ + H2O = (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate + NAD(P)H + H+

For diagram click here.

Systematic name: isopentenyl-diphosphate:NADP+ oxidoreductase

Comments: Forms part of an alternative, nonmevalonate pathway for terpenoid biosynthesis (for diagram, click here). The enzyme acts in the reverse direction producing a 5:1 mixture of isopentenyl diphosphate and dimethyallyl diphosphate.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Rohdich, F., Hecht, S., Gärtner, K., Adam, P., Krieger, C., Amslinger, S., Arigoni, D., Bacher, A. and Eisenreich, W. Studies on the nonmevalonate terpene biosynthetic pathway: Metabolic role of IspH (LytB) protein. Proc. Natl. Acad. Sci. USA 99 (2002) 1158-1163. [PMID: 11818558]

2. Hintz, M., Reichenberg, A., Altincicek, B., Bahr, U., Gschwind, R.M., Kollas, A.-K., Beck, E., Wiesner, J., Eberl, M. and Jomaa, H. Identification of (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate as a major activator for human αγ T cells in Escherichia coli. FEBS Lett. 509 (2001) 317-322. [PMID: 11741609]

3. Charon, L., Pale-Grosdemange, C. and Rohmer, M. On the reduction steps in the mevalonate independent 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway for isoprenoid biosynthesis in the bacterium Zymomonas mobilis. Tetrahedron Lett. 40 (1999) 7231-7234.

[EC 1.17.1.2 created 2003]

EC 1.17.1.3

Common name: leucoanthocyanidin reductase

Reaction: (2R,3S)-catechin + NADP+ + H2O = 2,3-trans-3,4-cis-leucocyanidin + NADPH + H+

Other name(s): leucocyanidin reductase

Systematic name: (2R,3S)-catechin:NADP+ 4-oxidoreductase

Comments: Catalyses the synthesis of catechin-4β-ol and the related flavan-3-ols afzelechin and gallocatechin, which are initiating monomers in the synthesis of plant polymeric proanthocyanidins or condensed tannins. While 2,3-trans-3,4-cis-leucocyanidin is the preferred flavan-3,4-diol substrate, 2,3-trans-3,4-cis-leucodelphinidin and 2,3-trans-3, 4-cis-leucopelargonidin can also act as substrates, but more slowly. NADH can replace NADPH but is oxidized more slowly.

References:

1. Tanner, G.J. and Kristiansen, K.N. Synthesis of 3,4-cis-[3H]leucocyanidin and enzymatic reduction to catechin. Anal. Biochem. 209 (1993) 274-277. [PMID: 8470799]

2. Tanner, G.J., Francki, K.T., Abrahams, S., Watson, J.M., Larkin, P.J. and Ashton, A.R. Proanthocyanidin biosynthesis in plants: Purification of legume leucoanthocyanidin reductase and molecular cloning of its cDNA. J. Biol. Chem. 278 (2003) 31647-31656. [PMID: 12788945]

[EC 1.17.1.3 created 2003]

EC 1.17.4.3

Common name: 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase

Reaction: (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate + H2O + protein-disulfide = 2-C-methyl-D-erythritol 2,4-cyclodiphosphate + protein-dithiol

For diagram click here.

Systematic name: (E)-4-hydroxy-3-methylbut-2-en-1-yl-diphosphate:protein-disulfide oxidoreductase (hydrating)

Comments: Forms, in the reverse direction, part of an alternative, nonmevalonate pathway for terpenoid biosynthesis (for diagram, click here).

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Hecht, S., Eisenreich, W., Adam, P., Amslinger, S., Kis, K., Bacher, A., Arigoni, Studies on the nonmevalonate pathway to terpenes: the role of the GcpE (IspG) protein. Proc. Natl. Acad. Sci. USA 98 (2001) 14837-14842. [PMID: 11752431]

[EC 1.17.4.3 created 2003]

*EC 1.20.4.2

Common name: methylarsonate reductase

Reaction: methylarsonate + 2 glutathione = methylarsonite + glutathione disulfide

For diagram click here.

Other name(s): MMA(V) reductase

Systematic name: gluthathione:methylarsonate oxidoreductase

Comments: The product, Me-As(OH)2 (methylarsonous acid), is biologically methylated by EC 2.1.1.137, arsenite methyltransferase, to form cacodylic acid (dimethylarsinic acid).

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Zakharyan, R.A. and Aposhian, H.V. Enzymatic reduction of arsenic compounds in mammalian systems: the rate-limiting enzyme of rabbit liver arsenic biotransformation is MMA(V) reductase. Chem. Res. Toxicol. 12 (1999) 1278-1283. [PMID: 10604879]

[EC 1.20.4.2 created 2000 as EC 1.97.1.7, transfered 2001 to EC 1.20.4.2, modified 2003]

EC 1.21.4 With a disulfide as acceptor

EC 1.21.4.1

Common name: D-proline reductase (dithiol)

Reaction: 5-aminopentanoate + lipoate = D-proline + dihydrolipoate

For diagram click here.

Systematic name: 5-aminopentanoate:lipoate oxidoreductase (cyclizing)

Comments: The reaction is observed only in the direction of D-proline reduction. Other dithiols can function as reducing agents; the enzyme contains a pyruvoyl group and a selenocysteine residue, both essential for activity.

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number: 37255-43-9

References:

1. Hodgins, D.S. and Abeles, R.H. Studies of the mechanism of action of D-proline reductase: the presence on covalently bound pyruvate and its role in the catalytic process. Arch. Biochem. Biophys. 130 (1969) 274-285. [PMID: 5778643]

2. Stadtman, T.C. and Elliott, P. Studies on the enzymic reduction of amino acids. II. Purification and properties of a D-proline reductase and a proline racemase from Clostridium sticklandii. J. Biol. Chem. 228 (1957) 983-997.

3. Kabisch, U.C., Gräntzdörffer, A., Schierhorn, A., Rücknagel, K.P, Andreesen, J.R. and Pich, A. Identification of D-proline reductase from Clostridium sticklandii as a selenoenzyme and indications for a catalytically active pyruvoyl group derived from a cysteine residue by cleavage of a proprotein. J. Biol. Chem. 274 (1999) 8445-8454. [PMID: 10085076]

[EC 1.21.4.1 created 1972 as EC 1.4.4.1, modified 1982 (EC 1.4.1.6 created 1961, incorporated 1982), transferred 2003 to EC 1.21.4.1]

EC 1.21.4.2

Common name: glycine reductase

Reaction: acetyl phosphate + ammonia + thioredoxin disulfide = glycine + phosphate + thioredoxin

Systematic name: acetyl-phosphate ammonia:thioredoxin disulfide oxidoreductase (glycine-forming)

Comments: The reaction is observed only in the direction of glycine reduction. The enzyme from Eubacterium acidaminophilum consists of subunits A, B and C. Subunit B contains selenocysteine and a pyruvoyl group, and is responsible for glycine binding and ammonia release. Subunit A, which also contains selenocysteine, is reduced by thioredoxin, and is needed to convert the carboxymethyl group into a ketene equivalent, in turn used by subunit C to produce acetyl phosphate. Only subunit B distinguishes this enzyme from EC 1.21.4.3 (sarcosine reductase) and EC 1.21.4.4 (betaine reductase).

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Wagner, M., Sonntag, D., Grimm, R., Pich, A. Eckerskorn, C., Söhling, B. and Andreesen, J.R. Substrate-specific selenoprotein B of glycine reductase from Eubacterium acidaminophilum. Eur. J. Biochem. 260 (1999) 38-49. [PMID: 10091582]

2. Bednarski, B., Andreesen, J.R. and Pich, A. In vitro processing of the proproteins GrdE of protein B of glycine reductase and PrdA of D-proline reductase from Clostridium sticklandii: formation of a pyruvoyl group from a cysteine residue. Eur. J. Biochem. 268 (2001) 3538-3544. [PMID: 11422384]

[EC 1.21.4.2 created 2003]

EC 1.21.4.3

Common name: sarcosine reductase

Reaction: acetyl phosphate + methylamine + thioredoxin disulfide = N-methylglycine + phosphate + thioredoxin

Glossary: sarcosine = N-methylglycine

Systematic name: acetyl-phosphate methylamine:thioredoxin disulfide oxidoreductase (N-methylglycine-forming)

Comments: The reaction is observed only in the direction of sarcosine reduction. The enzyme from Eubacterium acidaminophilum consists of subunits A, B and C. Subunit B contains selenocysteine and a pyruvoyl group, and is responsible for sarcosine binding and methylamine release. Subunit A, which also contains selenocysteine, is reduced by thioredoxin, and is needed to convert the carboxymethyl group into a ketene equivalent, in turn used by subunit C to produce acetyl phosphate. Only subunit B distinguishes this enzyme from EC 1.21.4.2 (glycine reductase) and EC 1.21.4.4 (betaine reductase).

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Wagner, M., Sonntag, D., Grimm, R., Pich, A. Eckerskorn, C., Söhling, B. and Andreesen, J.R. Substrate-specific selenoprotein B of glycine reductase from Eubacterium acidaminophilum. Eur. J. Biochem. 260 (1999) 38-49. [PMID: 10091582]

2. Hormann, K. and Andreesen, J.R. Reductive cleavage of sarcosine and betaine by Eubacterium acidaminophilum via enzyme systems different from glycine reductase. Arch. Microbiol. 153 (1989) 50-59.

[EC 1.21.4.3 created 2003]

EC 1.21.4.4

Common name: betaine reductase

Reaction: acetyl phosphate + trimethylamine + thioredoxin disulfide = N,N,N-trimethylglycine + phosphate + thioredoxin

Glossary: betaine = N,N,N-trimethylglycine

Systematic name: acetyl-phosphate trimethylamine:thioredoxin disulfide oxidoreductase (N,N,N-trimethylglycine-forming)

Comments: The reaction is observed only in the direction of betaine reduction. The enzyme from Eubacterium acidaminophilum consists of subunits A, B and C. Subunit B contains selenocysteine and a pyruvoyl group, and is responsible for betaine binding and trimethylamine release. Subunit A, which also contains selenocysteine, is reduced by thioredoxin, and is needed to convert the carboxymethyl group into a ketene equivalent, in turn used by subunit C to produce acetyl phosphate. Only subunit B distinguishes this enzyme from EC 1.21.4.2 (glycine reductase) and EC 1.21.4.3 (sarcosine reductase).

Links to other databases: BRENDA, EXPASY, KEGG, WIT, CAS registry number:

References:

1. Wagner, M., Sonntag, D., Grimm, R., Pich, A. Eckerskorn, C., Söhling, B. and Andreesen, J.R. Substrate-specific selenoprotein B of glycine reductase from Eubacterium acidaminophilum. Eur. J. Biochem. 260 (1999) 38-49. [PMID: 10091582]

2. Bednarski, B., Andreesen, J.R. and Pich, A. In vitro processing of the proproteins GrdE of protein B of glycine reductase and PrdA of D-proline reductase from Clostridium sticklandii: formation of a pyruvoyl group from a cysteine residue. Eur. J. Biochem. 268 (2001) 3538-3544. [PMID: 11422384]

[EC 1.21.4.4 created 2003]


Return to list of new enzymes in supplement 9
Return to Enzymes Home Page.