EC 3 Hydrolases

(excluding peptidases)

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Recommended name: acetylalkylglycerol acetylhydrolase

Reaction: 2-acetyl-1-alkyl-sn-glycerol + H2O = 1-alkyl-sn-glycerol + acetate

Other name(s): alkylacetylglycerol acetylhydrolase

Systematic name: 2-acetyl-1-alkyl-sn-glycerol acetylhydrolase

Comments: hydrolysis of the acetyl group from the 1-alkyl-2-acetyl and 1-alkyl-3-acetyl substrates occurs at apparently identical rates. The enzyme from Erlich ascites cells is membrane-bound. It differs from lipoprotein lipase (EC since 1,2-diacetyl-sn-glycerols are not substrates. It also differs from EC (1-acetyl-2-alkyl-glycerophosphocholine esterase)


1. Blank, M.L., Smith, Z.L., Cress, E.A., Snyder, F. Characterization of the enzymatic hydrolysis of acetate from alkylacetylglycerols in the de novo pathway of PAF biosynthesis. Biochim. Biophys. Acta 1042 (1990) 153-158. [PMID: 2302414]


Recommended name: acetylxylan esterase

Reaction: Deacetylation of xylans and xylo-oligosaccharides

Systematic name: acetylxylan esterase

Comments: catalyses the hydrolysis of acetyl groups from polymeric xylan, acetylated xylose, acetylated glucose, α-napthyl acetate, p-nitrophenyl acetate but not from triacetylglycerol. Does not act on acetylated mannan or pectin.


1. Sundberg, M., Poutanen, K. Purification and properties of two acetylxylan esterases of Trichoderma reesei. Biotechnol. Appl. Biochem. 13 (1991) 1-11.

2. Poutanen, K., Sundberg, M., Korte, H., Puls, J. Deacetylation of xylans by acetyl esterases of Trichoderma reesei. Appl. Microbiol. Biotechnol. 33 (1990) 506-510.

3. Margolles-Clark, E., Tenkanen, M., Söderland, H., Penttilä, M. Acetyl xylan esterase from Trichoderma reesei contains an active site serine and a cellulose binding domain. Eur. J. Biochem. 237 (1996) 553-560. [PMID: 8647098]


Recommended name: dodecanoyl-[acyl-carrier protein] hydrolase

Reaction: dodecanoyl-[acyl-carrier protein] + H2O = [acyl-carrier protein] + dodecanoate

Other name(s): lauryl-acyl-carrier-protein hydrolase; dodecanoyl-acyl-carrier-protein hydrolase; dodecyl-acyl-carrier protein hydrolase

Systematic name: dodecanoyl-[acyl-carrier-protein] hydrolase

Comments: acts on the acyl-carrier-protein thioester of C12 and, with a much lower activity, C14 fatty acids. The derivative of oleic acid is hydrolysed very slowly (compare EC


1. Pollard, M.R., Anderson, L., Fan, C., Hawkins, D.J., Davies, H.M. A specific acyl-ACP thioesterase implicated in medium-chain fatty acid production in immature cotyledons of Umbellularia californica. Arch. Biochem. Biophys. 284 (1991) 306-312. [PMID: 1989513]

2. Davies, H.M., Anderson, L., Fan, C., Hawkins, D.J. Developmental induction, purification, and further characterization of 12:0-ACP thioesterase from immature cotyledons of Umbellularia californica. Arch. Biochem. Biophys. 290 (1991) 37-45. [PMID: 1898097]


Recommended name: palmitoyl-(protein) hydrolase

Reaction: palmitoyl-(protein) + H2O = palmitate + (protein)

Other name(s): palmitoyl-protein thioesterase

Systematic name: palmitoyl-(protein) hydrolase

Comments: specific for long-chain thioesters of fatty acids. Hydrolyses fatty acids from S-acylated cysteine residues in proteins, palmitoyl cysteine and palmitoyl-CoA.


1. Camp, L.A., Hofmann, S.L. Assay and isolation of palmitoyl-protein thioesterase from bovine brain using palmitoylated H-Ras as substrate. Methods Enzymol. 250 (1995) 336-347. [PMID: 7651163]

2. Schriner, J.E., Yi, W., Hofmann, S.L. cDNA and genomic cloning of human palmitoyl-protein thioesterase (PPT), the enzyme defective in infantile neuronal ceroid lipofuscinosis. Genomics, 34 (1996) 317-322. [PMID: 8786130]

3. Verkruyse, L.A., Hofmann, S.L. Lysosomal targeting of palmitoyl-protein thioesterase. J. Biol. Chem. 271 (1996) 15831-15836. [PMID: 8663305]


Recommended name: 4-hydroxybenzoyl-CoA thioesterase

Reaction: 4-hydroxybenzoyl-CoA + H2O = 4-hydroxybenzoate + CoA

Systematic name: 4-hydroxybenzoyl-CoA hydrolase

Comments: this enzyme is part of the bacterial 2,4-dichlorobenzoate degradation pathway.


1.Chang, K.H., Liang, P.H., Beck, W., Scholten, J.D., Dunaway-Mariano, D. Isolation and characterization of the three polypeptide components of 4-chlorobenzoate dehalogenase from Pseudomonas sp. strain CBS-3. Biochemistry 31 (1992) 5605-5610. [PMID: 1610806]

2.Dunaway-Mariano, D., Babbitt, P.C. On the origins and functions of the enzymes of the 4-chlorobenzoate to 4-hydroxybenzoate converting pathway. Biodegradation 5 (1994) 259-276. [PMID: 7765837]


Recommended name: phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase

Reaction: phosphatidylinositol-3,4,5-trisphosphate + H2O = phosphatidyl inositol-4,5-bisphosphate + phosphate

Systematic name: phosphatidylinositol-3,4,5-trisphosphate 3-phosphohydrolase

Comments: requires magnesium. Does not dephosphorylate inositol 4,5-bisphosphate


1. Kabuyama, Y., Nakatsu, N., Homma, Y., Fukui, Y. Purification and characterization of phosphatidyl inositol-3,4,5-trisphosphate phosphatase in bovine thymus. Eur. J. Biochem. 238 (1996) 350-356. [PMID: 8681945]


Recommended name: 2-deoxyglucose-6-phosphatase

Reaction: 2-deoxy-D-glucose 6-phosphate + H2O = 2-deoxy-D-glucose + phosphate

Other name(s): 2-deoxyglucose-6-phosphate phosphatase

Systematic name: 2-deoxy-D-glucose-6-phosphate phosphohydrolase

Comments: also active towards fructose 1-phosphate


1. Johnston, M., Andrews, S., Brinkman, R., Cooper, J., Ding, H., Dover, J., Du, Z., Favello, A., Fulton, L., Gattung, S., Geisel, C., Kirsten, J., Kucaba, T., Hillier, L., Jier, M., Johnston, L., Langston, Y., Latreille, P., Louis, E.J., Macri, C., Mardis, E., Menezes, S., Mouser, L., Nhan, M., Rifkin, L., Riles, L., St.Peter, H., Trevaskis, E., Vaughan, K., Vignati, D., Wilcox, L., Wohldman, P., Waterston, R., Wilson, R., Vaudin, M. Complete nucleotide sequence of Saccharomyces cerevisiae chromosome VIII. Science 265 (1994) 2077-2082. [PMID: 8091229]

2. Randez-Gil, F., Blasco, A., Prieto, J.A., Sanz, P. DOGR1 and DOGR2: two genes from Saccharomyces cerevisiae that confer 2-deoxyglucose resistance when overexpressed. Yeast 11 (1995) 1233-1240. [PMID: 8553694]


Recommended name: CC-preferring endodeoxyribonuclease

Reaction: endonucleolytic cleavage to give 5'-phosphooligonucleotide end-products, with a preference for cleavage within the sequence CC

Other name(s): Streptomyces glaucescens exocytoplasmic dodeoxyribonuclease

Comments: prefers CC sites in double-stranded circular and linear DNA. Greater affinity for double-stranded than single-stranded DNA. Produces nicks, generating double-stranded fragments with 5'- and/or 3'-protruding single-stranded tails. Requires magnesium ions for activity. The endonuclease from Chlorella-like green algae infected with NYs-1 virus 4[1] may be the same enzyme.


1. Xia, Y.N., Morgan, R., Schildkraut, I., Van Etten, J.L. A site-specific single-strand endonuclease activity induced by NYs-1 virus-infection of a Chlorella-like green-alga. Nucleic Acids Res. 16 (1988) 9477-9487. [PMID: 3186439]

2. Aparicio, J.F., Lopez-Otin, C., Cal, S., Sanchez, J. A Streptomyces glaucescens endodeoxyribonuclease which shows a strong preference for CC dinucleotide. Eur. J. Biochem. 205 (1992) 695-699. [PMID: 1533367]


Recommended name: α-glucosiduronase

Reaction: an α-D-glucuronoside + H2O = an alcohol + D-glucuronate

Other name(s): α-glucuronidase

Systematic name: α-D-glucosiduronate glucuronohydrolase

Comments: considerable differences in the specificities of the enzymes from different fungi for α-D-glucosiduronates have been reported. Activity is also found in the snail.


1. Puls, J. α-Glucuronidases in the hydrolysis of wood xylans. In Xylans and Xylanases (J. Visser et al., Eds.), Elsevier, Amsterdam, (1992) pp. 213-224.

2. Uchida, H., Nanri, T., Kawabata, Y., Kusakabe, I., Murakami, K. Purification and characterization of intracellular α-glucuronidase from Aspergillus niger. Biosci. Biotechnol. Biochem. 56 (1992) 1608-1615.


Recommended name: lacto-N-biosidase

Reaction: β-D-Gal-(1[arrow to right]3)-β-D-GlcNAc-(1[arrow to right]3)-β-D-Gal-(1[arrow to right]4)-D-Glc + H2O = β-D-Gal-(1[arrow to right]3)-D-GlcNAc + β-D-Gal-(1[arrow to right]4)-D-Glc

Lacto-N-tetraose + H2O = lacto-N-biose + lactose

Systematic name: oligosaccharide lacto-N-biosylhydrolase

Comments: the enzyme from Streptomyces specifically hydrolyses the terminal lacto-N-biosyl residue (β-D-Gal-(1[arrow to right]3)-D-GlcNAc) from the non-reducing end of oligosaccharides with the structure β-D-Gal-(1[arrow to right]3)-β-D-GlcNAc-(1[arrow to right]3)-β-D-Gal-(1[arrow to right]R). Lacto-N-hexaose (β-D-Gal-(1[arrow to right]3)-β-D-GlcNAc-(1[arrow to right]3)-β-D-Gal-(1[arrow to right]3)-β-D-GlcNAc-(1[arrow to right]3)-β-D-Gal-(1[arrow to right]4)-D-Glc) is hydrolysed to form first lacto-N-tetraose plus lacto-N-biose, with the subsequent formation of lactose. Oligosaccharides in which the non-reducing terminal Gal or the penultimate GlcNAc are replaced by fucose or sialic acid are not substrates. Asialo GM1 tetraose (β-D-Gal-(1[arrow to right]3)-β-D-GalNAc-(1[arrow to right]3)-β-D-Gal-(1[arrow to right]4)-D-Glc) is hydrolysed very slowly, but lacto-N-neotetraose (β-D-Gal-(1[arrow to right]4)-β-D-GalNAc-(1[arrow to right]3)-β-D-Gal-(1[arrow to right]4)-D-Glc) is not a substrate


1. Sano, M., Hayakawa, K., Kato, I. An enzyme releasing lacto-N-biose from oligosaccharides. Proc. Natl. Acad. Sci. U.S.A. 89 (1992) 8512-8516. [PMID: 1528855]

2. Sano, M., Hayakawa, K., Kato, I. Purification and characterization of an enzyme releasing lacto-N-biose from oligosaccharides with type 1 chain. J. Biol. Chem. 268 (1993) 18560-18566. [PMID: 7689556]


Recommended name: 4-α-D-{(1[arrow to right]4)-α-D-glucano}trehaose trehalohydrolase

Reaction: hydrolysis of α-(1[arrow to right]4)-D-glucosidic linkage in 4-α-D-{(1[arrow to right]4)-α-D-glucanosyl}n trehalose to yield trehalose and α-(1[arrow to right]4)-D-glucan

Other name(s): malto-oligosyltrehalose trehalohydrolase

Systematic name: 4-α-D-{(1[arrow to right]4)-α-D-glucano}trehaose glucanohydrolase (trehalose-producing)


1. Maruta, K., Nakada, T., Kubota, M., Chaen, H., Sugimoto, T., Kurimoto, M., Tsujisaka, Y. Formation of trehalose from maltooligosaccharides by a novel enzymatic system. Biosci. Biotechnol. Biochem. 59 (1995) 1829-1834. [PMID: 8534970]

2. Nakada, T., Maruta, K., Mitsuzumi, H., Kubota, M., Chaen, H., Sugimoto, T., Kurimoto M., Tsujisaka, Y. Purification and characterization of a novel enzyme, maltooligosyl trehalose trehalohydrolase, from Arthrobacter sp. Q36. Biosci. Biotechnol. Biochem. 59 (1995) 2215-2218. [PMID: 8611745]

3. Nakada, T., Ikegami, S., Chaen, H., Kubota, M., Fukuda, S., Sugimoto, T., Kurimoto, M., Tsujisaka, Y. Purification and characterization of thermostable maltooligosyl trehalose trehalohydrolase from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius. Biosci. Biotechnol. Biochem. 60 (1996) 267-270. [PMID: 9063974]


Recommended name: formamidopyrimidine-DNA glycosylase

Reaction: hydrolyses the deoxyribosyl bond N-6 of either 2,6-diamino-4-hydroxy-5(N-methyl)formamidopyrimidine (FAPY) or 4,6-diamino-5-formamidopyrimidine, to release the pyrimidine

Systematic name: formamidopyrimidine-DNA glycosyl hydrolase

Comments: may play a significant role in processes leading to recovery from mutagenesis and/or cell death by alkylating agents. Also involved in the GO system responsible for removing an oxidatively damaged form of guanine (7,8-dihydro-8-oxoguanine) from DNA


1. Boiteux, S., O'Connor, T.R., Laval, J. Formamidopyrimidine-DNA glycosylase of Escherichia coli: cloning and sequencing of the fpg structural gene and overproduction of the protein. EMBO J. 6 (1987) 3177-3183. [PMID: 3319582]


Recommended name: arylalkyl acylamidase

Reaction: N-acetylarylalkylamine + H2O = arylalkylamine + acetate

Other name(s): aralkyl acylamidase

Systematic name: N-acetylarylalkylamine amidohydrolase

Comments: identified in Pseudomonas putida. Strict specificity for N-acetyl arylalkylamines, including N-acetyl-2-phenylethylamine, N-acetyl-3-phenylpropylamine, N-acetyldopamine, N-acetyl-serotonin and melatonin. It also accepts arylalkyl acetates but not acetanilide derivatives, which are common substrates of aryl acylamidase (EC


1. Shimizu, S., Ogawa, J., Chung, M.C.-M., Yamada, H. Purification and characterization of a novel enzyme, arylalkyl acylamidase, from Pseudomonas putida Sc2. Eur. J. Biochem. 209 (1992) 375-382. [PMID: 1396711]


Recommended name: N-carbamoyl-D-amino acid hydrolase

Reaction: N-carbamoyl-D-amino acid + H2O = D-amino acid + NH3+ + CO2

Systematic name:N-carbamoyl-D-amino acid amidohydrolase

Comments: has strict stereospecificity for N-carbamoyl-D-amino acids and does not act upon the corresponding L-amino acids or N-formyl amino acids, N-carbamoyl-sarcosine, -citrulline, -allantoin and -ureidopropionate, which are substrates for other amidohydrolases.


1. Ogawa, J., Shimizu, S., Yamada, H. N-Carbamoyl-D-amino acid amidohydrolase from Comamonas sp. E222c; purification and characterization. Eur. J. Biochem. 212 (1993) 685-691. [PMID: 8462543]


Recommended name: glutathionylspermidine amidase

Reaction: N1-(γ-L-glutamyl-L-cysteinyl-glycyl)-speridine + H2O = γ-L-glutamyl-L-cysteinyl-glycine + spermidine (glutathionylspermidine + H2O = glutathione + spermidine)

Other name(s): glutathionylspermidine amidohydrolase (spermidine-forming)

Systematic name: γ-L-glutamyl-L-cysteinyl-glycine:spermidine amidase

Comments: spermidine is numbered so that atom N-1 is in the amino group of the aminopropyl part of the molecule. The enzyme from E. coli is bifunctional and also catalyses the glutathionylspermidine synthase (EC reaction, resulting in a net hydrolysis of ATP.


1. Bollinger, J.M., Kwon, D.S., Huisman, G.W., Kolter, R., Walsh, C.T. Glutathionylspermidine metabolism in E. coli. Purification, cloning, overproduction and characterization of a bifunctional glutathionylspermidine synthetase/amidase. J. Biol. Chem. 270 (1995) 14031-14041. [PMID: 7775463]


Recommended name: phthalyl amidase

Reaction: a phthalylamide + H2O = phthalic acid + a substituted amine

Systematic name: phthalyl-amide amidohydrolase

Comments: in the entry, "phthalyl" is used to mean "2-carboxybenzoyl". The enzyme from Xanthobacter agilis hydrolyses phthalylated amino acids, peptides, β-lactams, aromatic and aliphatic amines. The substituent on nitrogen may be an alkyl group, but may also be complex, giving an amino acid or peptide derivative. Substitutions on the phthalyl ring include 6-F, 6-NH2, 3-OH, and a nitrogen in the aromatic ring ortho to the carboxyl group attached to the amine. No cofactors are required


1. Briggs, B.S., Kreuzman, A.J., Whitesitt, C., Yeh, W.K., Zmijewski, M. Discovery, purification, and properties of o-phthalyl amidase from Xanthobacter agilis. J. Mol. Catalysis B: Enzymes 2 (1996) 53-69.

2. Black, T.D., Briggs, B.S., Evans, R., Muth, W.L., Vangala, S., Zmijewski, M.J. o-Phthalyl amidase in the synthesis of Loracarbef: process development using this novel biocatalyst. Biotechnol. Lett. 18 (1996) 875-880.

3. Costello, C., Kreuzman, A., Zmijewski, M. Selective deprotection of phthalyl protected proteins. Tetrahedron Lett. 37 (1996) 7469-7472.

4. Briggs, B.S., Zmijewski, M.J. Phthalyl amidase of Xanthobacter agilis. US Patent no. 5,445,959 (Aug. 29, 1995)


Recommended name: N-acetylgalactosamine-6-phosphate deacetylase

Reaction: N-acetyl-D-galactosamine 6-phosphate + H2O = D-galactosamine 6-phosphate + acetate

Systematic name: N-acetyl-D-galactosamine 6-phosphate amidohydrolase


1. Yamano, N., Matsushita, Y., Kamada, Y., Fujishima, S., Arita, M. Purification and characterization of N-acetylglucosamine 6-phosphate deacetylase with activity against N-acetylglucosamine from Vibrio cholerae non-O1. Biosci. Biotechnol. Biochem. 60 (1996) 1320-1323. [PMID: 8987551]


Recommended name: N-acyl-D-amino-acid deacylase

Reaction: N-acyl-D-amino acid + H2O = an acid + D-amino acid

Systematic name: N-acyl-D-amino acid amidohydrolase

Comments: the enzyme from Alcaligenes denitrificans subsp. xylosoxydans and Alcaligenes xylosoxydans subsp. xylosoxydans has wide specificity; hydrolyses N-acyl derivative of neutral D-amino acids. Used in separating D- and L-amino acids. Requires zinc.


1. Wakayama, M., Katsuno, Y., Hayashi, S., Miyamoto, Y., Sakai, K., Moriguchi, M. Cloning and sequencing of a gene encoding D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 and expression of the gene in Escherichia coli. Biosci. Biotechnol. Biochem. 59 (1995) 2115-2119. [PMID: 8541651]

2. Wakayama, M., Hayashi, S., Yatsuda, Y., Katsuno, Y., Sakai, K., Moriguchi, M. Overproduction of D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 in Escherichia coli and its purification. Protein Expr. Purif. 7 (1996) 395-399. [PMID: 8776758]


Recommended name: N-acyl-D-glutamate deacylase

Reaction: N-acyl-D-glutamate + H2O = carboxylate + D-glutamate

Systematic name: N-acyl-D-glutamate amidohydrolase

Comments: the enzyme from Alcaligenes xylosoxydans subsp. xylosoxydans and Pseudomonas sp. is specific for N-acyl-D-glutamate. Requires zinc.


1. Wakayama, M., Ahshika, T., Miyamoto, Y., Yoshikawa, T., Sonoda, Y., Sakai, K., Moriguchi, M. Primary structure of N-acyl-D-glutamate amidohydrolase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6. J. Biochem. (Tokyo) 118 (1995) 204-209. [PMID: 8537313]

2. Wakayama, M., Miura, Y., Oshima, K., Sakai, K., Moriguchi, M. Metal-characterization of N-acyl-D-glutamate amidohydrolase from Pseudomonas sp. strain 5f-1. Biosci. Biotechnol. Biochem. 59 (1995) 1489-1492. [PMID: 7549100]

3. Wakayama, M., Tsutsumi, T., Yada, H., Sakai, K., Moriguchi, M. Chemical modification of histidine residue of N-acyl-D-glutamate amidohydrolase from Pseudomonas sp. 5f-1. Biosci. Biotechnol. Biochem. 60 (1996) 650-653. [PMID: 8829533]


Recommended name: N-acyl-D-aspartate deacylase

Reaction: N-acyl-D-aspartate + H2O = a carboxylate + D-aspartate

Systematic name: N-acyl-D-aspartate amidohydrolase

Comments: the enzyme from Alcaligenes xylosoxydans subsp. xylosoxydans is specific for N-acyl-D-aspartate. Requires zinc.


1. Moriguchi, M., Sakai, K., Katsuno, Y., Maki, T., Wakayama, M. Purification and characterization of novel N-acyl-D-aspartate amidohydrolase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6. Biosci. Biotechnol. Biochem. 57 (1993) 1145-1148. [PMID: 7763985]

2. Wakayama, M., Watanabe, E., Takenaka, Y., Miyamoto, Y., Tau, Y., Sakai, K., Moriguchi, M. Cloning, expression and nucleotide sequence of the N-acyl-D-aspartate amidohydrolase gene from Alcaligenes xylosoxydans subsp. xylosoxydans A-6. J. Ferment. Bioeng. 80 (1995) 311-317.


Recommended name: methylenediurea deaminase

Reaction: (1) NH2-CO-NH-CH2-NH-CO-NH2 + H2O = N-(carboxyaminomethyl)urea + NH3+

(2) N-(carboxyaminomethyl)urea = N-(aminomethyl)urea + CO2 (spontaneous)

(3) N-(aminomethyl)urea + H2O = N-(hydroxymethyl)urea + NH3+ (spontaneous)

Other name(s): methylenediurease

Systematic name: methylenediurea aminohydrolase

Comments: the methylenediurea is hydrolysed and decarboxylated to give an aminated methylurea, which then spontaneously hydrolyses to hydroxymethylurea. The enzyme from Ochrobactrum anthropi also hydrolyses dimethylenetriurea and trimethylenetetraurea as well as ureidoglycolate, which is hydrolysed to urea and glyoxylate, and allantoate, which is hydrolysed to ureidoglycolate, ammonia and carbon dioxide.


1. Jahns, T., Schepp, R., Kaltwasser, H. Purification and characterisation of an enzyme from a strain of Ochrobactrum anthropi that degrades condensation products of urea and formaldehyde (ureaform). Can. J. Microbiol. 43 (1997) 1111-1117.


Recommended name: aliphatic nitrilase

Reaction: R-CN + H2O = R-COOH + NH3+

Systematic name: aliphatic nitrile aminohydrolase

Comments: preferentially hydrolyses aliphatic nitriles, some of which are apparently not substrates for other known nitrilases (EC Substrates include crotononitrile, acrylonitrile and glutaronitrile.


1. Kobayashi, M., Yanaka, N., Nagasawa, T., Yamada, H. Primary structure of an aliphatic nitrile-degrading enzyme, aliphatic nitrilase from Rhodococcus rhodochrous K22 and expression of its gene and identification of its active site residue. Biochemistry 31 (1992) 9000-9007. [PMID: 1390687]


Recommended name: UDP-sugar diphosphatase

Reaction: UDP-sugar + H2O = UMP + sugar 1-phosphate

Other name(s): nucleosidediphosphate-sugar pyrophosphatase; nucleosidediphosphate-sugar diphosphatase; UDP-sugar hydrolase; UDP-sugar pyrophosphatase

Systematic name: UDP-sugar sugarphosphohydrolase

Comments: a divalent cation is required for activity. UDP-sugar is the best substrate, although other nucleoside-sugar diphosphates are used as substrates with similar Km values but much lower maximum velocities. Thus, this enzyme has a specificity distinct from that of ADP-sugar diphosphatase (EC Some but not all enzymes of this class also appear to have 5'-nucleotidase (see EC activity.


1. Garrett, A.R., Johnson, L.A., Beacham, I.R. Isolation, molecular characterization and expression of the ushB gene of Salmonella typhimurium which encodes a membrane bound UDP-sugar hydrolase. Mol. Microbiol. 3 (1989) 177-186. [PMID: 2548058]

2. Glaser, L., Melo, A., Paul, R. Uridine diphosphate sugar hydrolase. Purification of enzyme and protein inhibitor. J. Biol. Chem. 242 (1987) 1944-1954.


Recommended name: 4-chlorobenzoyl-CoA dehalogenase

Reaction: 4-chlorobenzoyl-CoA + H2O = 4-hydroxybenzoyl CoA + chloride

Systematic name: 4-chlorobenzoyl CoA chlorohydrolase

Comments: specific for dehalogenation at the 4-position. Can dehalogenate substrates bearing fluorine, chlorine, bromine and iodine in the 4-position. This enzyme is part of the bacterial 2,4-dichlorobenzoate degradation pathway.


1. Chang, K.H., Liang, P.H., Beck, W., Scholten, J.D., Dunaway-Mariano, D. Isolation and characterization of the three polypeptide components of 4-chlorobenzoate dehalogenase from Pseudomonas sp. strain CBS-3. Biochemistry 31 (1992) 5605-5610. [PMID: 1610806]

2. Crooks, G.P., Copley, S.D. Purification and characterization of 4-chlorobenzoyl CoA dehalogenase from Arthrobacter sp. strain 4-CB1. Biochemistry, 33 (1994) 11645-11649. [PMID: 7918379]


Recommended name: phosphonoacetate hydrolase

Reaction: phosphonoacetate + H2O = acetate + phosphate

Systematic name: phosphonoacetate phosphonohydrolase

Comments: a zinc-dependent enzyme.


1. McGrath, J.W., Wisdom, G.B., McMullan, G., Larkin, M.J., Quinn, J.P. The purification and properties of phosphonoacetate hydrolase, a novel carbon-phosphorus bond-cleavage enzyme from Pseudomonas fluorescens 23F. Eur. J. Biochem. 234 (1995) 225-230. [PMID: 8529644]



Recommended name: exo-α-sialidase

Reaction: hydrolysis of α-(2[arrow to right]3)-, α-(2[arrow to right]6)-, α-(2[arrow to right]8)- glycosidic linkages of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates

Other name(s): neuraminidase; sialidase

Systematic name: acetylneuraminyl hydrolase

Comments: the enzyme does not act on 4-O-acetylated sialic acids. An endo-α-sialidase activity is listed as EC See also EC


1. Schauer, R. Sialic acids. Adv. Carbohydr. Chem. Biochem. 40 (1982) 131-234.

2. Cabezas, J.A. Some questions and suggestions on the type references of the official nomenclature (IUB) for sialidase(s) and endosialidase. Biochem. J. 278 (1991) 311-312. [PMID: 1883340]


Recommended name: maltose-6'-phosphate glucosidase

Reaction: maltose 6'-phosphate + H2O = D-glucose 6-phosphate + D-glucose

Other name(s): phospho-α-glucosidase

Systematic name: maltose-6'-phosphate 6-phosphoglucohydrolase

Comments: hydrolyses a variety of 6-phospho-D-glucosides, including maltose 6-phosphate, α,α-trehalose 6-phosphate, sucrose 6-phosphate and p-nitrophenyl-α-D-glucopyranoside 6-phosphate (as a chromogenic substrate). The enzyme is activated by FeII, MnII, CoII and NiII. It is rapidly inactivated in air.


1. Thompson, J., Gentry-Weeks, C.R., Nguyen, N.Y., Folk, J.E., Robrish, S.A. Purification from Fusobacterium mortiferum ATCC 25557 of a 6-phosphoryl-O-α-D-glucopyranosyl:6-phosphoglucohydrolas that hydrolyses maltose 6-phosphate and related phospho-α-D-glucosides. J. Bacteriol. 177 (1995) 2505-2512. [PMID: 7730284]


Recommended name: endo-α-sialidase

Reaction: endohydrolysis of (2[arrow to right]8)-α-sialosyl linkages in oligo- or poly(sialic) acids

Other names: endo-N-acylneuraminidase; endoneuraminidase; poly(α-2,8-sialoside); α-2,8-sialosylhydrolase; endo-N-acetylneuraminidase; poly(α-2,8-sialosyl); endo-N-acetylneuraminidase

Systematic name: polysialoside (2[arrow to right]8)-α-sialosylhydrolase

Comments: although the name endo-N-acetylneuraminidase has also been used for this enzyme, this is misleading since its activity is not restricted to acetylated substrates. An exo-α-sialidase activity is listed as EC See also EC


1. Finne, J., Mäkelä, P.H. Cleavage of the polysialosyl units of brain glycoproteins by a bacteriophage endosialidase. Involvement of a long oligosaccharide segment in molecular interactions of polysialic acid. J. Biol. Chem. 260 (1985) 1265-1270. [PMID: 3968060]

2. Hallenbeck, P.C., Vimr, E.R., Yu, F., Bassler, B., Troy, F.A. Purification and properties of a bacteriophage-induced endo-N-acetylneuraminidase specific for poly-α-2,8-sialosyl carbohydrate units. J. Biol. Chem. 262 (1987) 3553-3561. [PMID: 3546309]

3. Kitajima, K., Inoue, S., Inoue, Y., Troy, F.A. Use of a bacteriophage-derived endo-N-acetylneuraminidase and an equine antipolysialyl antibody to characterize the polysialyl residues in salmonid fish egg polysialoglycoproteins. Substrate and immunospecificity studies. J. Biol. Chem. 263 (1988) 18269-18276. [PMID: 3142874]

4. Kwiatkowski, B., Boschek, B., Thiele, H., Stirm, S. Endo-N-acetylneuraminidase associated with bacteriophage particles. J. Virol. 43 (1982) 697-704. [PMID: 7109038]

5. Pelkonen, S., Pelkonen, J., Finne, J. Common cleavage pattern of polysialic acid by bacteriophage endosialidases of different properties and origins. J. Virol. 65 (1989) 4409-4416. [PMID: 2778882]

6. Tomlinson, S., Taylor, P.W. Neuraminidase associated with coliphage E that specifically depolymerizes the Escherichia coli K1 capsular polysaccharide. J. Virol. 55 (1985) 374-378. [PMID: 3894684]

7. Cabezas, J.A. Some questions and suggestions on the type references of the official nomenclature (IUB) for sialidase(s) and endosialidase. Biochem. J. 278 (1991) 311-312. [PMID: 1883340]


Recommended name: glucan 1,4-α-maltohydrolase

Reaction: hydrolysis of (1[arrow to right]4)-α-D-glucosidic linkages in polysaccharides so as to remove successive α-maltose residues from the non-reducing ends of the chains

Other name(s): maltogenic α-amylase

Systematic name: 1,4-α-D-glucan α-maltohydrolase

Comments: acts on starch and related polysaccharides and oligosaccharides. The product is α-maltose; cf. EC


1. Diderichsen, B., Christiansen, L. Cloning of a maltogenic α-amylase from Bacillus stearothermophilus. Microbiol. Lett. 56 (1988) 53-60.

2. Outtrup, H., Norman, B.E. Properties and application of a thermostable maltogenic amylase produced by a strain of Bacillus modified by recombinant-DNA. Starke 36 (1984) 405-411.


Recommended name: ADP-sugar diphosphatase

Reaction: ADP-sugar + H2O = AMP + sugar 1-phosphate

Other name(s): ADP-sugar pyrophosphatase

Systematic name: ADP-sugar sugarphosphohydrolase

Comments: has a specificity that is distinct from that of UDP-sugar diphosphatase (EC

References: 4160

1. Rodriguez, P., Bass, S.T., Hansen, R.G. A pyrophosphatase from mammalian tissues specific for derivatives of ADP. Biochim. Biophys. Acta 167 (1968) 199-201. [PMID: 5686292]

Addition required by proposed new entry EC


Recommended name: 4-chlorobenzoate dehalogenase

Reaction: 4-chlorobenzoate + H2O = 4-hydroxybenzoate + chloride

Systematic name: 4-chlorobenzoate chlorohydrolase

Comments: Catalyses the first step in the degradation of chlorobenzoate in Pseudomonas. In many microorganisms, this activity comprises three separate enzymes, EC (4-chlorobenzoate-CoA ligase), EC (4-chlorobenzoyl-CoA dehalogenase) and EC (4-hydroxybenzoyl-CoA thioesterase).


1. Heppel, L.A., Porterfield, V.T. Enzymatic dehalogenation of certain brominated and chlorinated compounds. J. Biol. Chem. 176 (1948) 763-769.



Recommended name:epoxide hydrolase

References: 2266, 2975, 3657, 3658 (not 3757-3758)

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