EC 4 Lyases

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Recommended name: indolepyruvate decarboxylase

Reaction: 3-(indol-3-yl)pyruvate = 2-(indol-3-yl)acetaldehyde + CO2

Systematic name: indol-3-yl-pyruvate carboxy-lyase

Comments: thiamine diphosphate- and Mg2+-dependent. More specific than EC


1. Koga, J. Structure and function of indolepyruvate decarboxylase, a key enzyme in indole-3-pyruvic acid biosynthesis. Biochim. Biophys. Acta 1249 (1995) 1-13. [PMID: 7766676]


Recommended name: 5-guanidino-2-oxopentanoate decarboxylase

Reaction: 5-guanidino-2-oxo-pentanoate = 4-guanidinobutanal + CO2

Other name(s): α-ketoarginine decarboxylase

Systematic name: 2-oxo-5-guanidinopentanoate carboxy-lyase

Comments: enzyme activity is dependent on the presence of thiamine diphosphate and a divalent cation.


1.Vanderbilt, A.S., Gaby, N.S., Rodwell, V.W. Intermediates and enzymes between α-ketoarginine and γ-guanidinobutyrate in the L-arginine catabolic pathway of Pseudomonas putida. J. Biol. Chem. 250 (1975) 5322-5329. [PMID: 237915]


Recommended name: arylmalonate decarboxylase

Reaction: 2-aryl-2-methylmalonate = 2-arylpropionate + CO2

Other name(s): AMDASE

Systematic name: 2-aryl-2-methylmalonate carboxy-lyase


1. Miyamoto, K., Ohta, H. Cloning and heterologous expression of a novel arylmalonate decarboxylase gene from Alcaligenes bronchisepticus KU 1201. Appl. Microbiol. Biotechnol. 38 (1992) 234-238. [PMID: 1369144]


Recommended name: 4-oxalocrotonate decarboxylase

Reaction: 4-oxalocrotonate = 2-oxopent-4-enoate + CO2

Systematic name: 4-oxalocrotonate carboxy-lyase

Comments: involved in the meta-cleavage pathway for the degradation of phenols, cresols and catechols


1.Shingler, V., Marklund, U., Powlowski, J. Nucleotide sequence and functional analysis of the complete phenol/3,4-dimethylphenol catabolic pathway of Pseudomonas sp. strain CF600. J. Bacteriol. 174 (1992) 711-724. [PMID: 1732207]


Recommended name: hydroxynitrilase

Reaction: 2-hydroxyisobutyronitrile = cyanide + acetone

Other name(s): hydroxynitrile lyase; oxynitrilase

Systematic name: 2-hydroxyisobutyronitrile acetone-lyase

Comments: the enzyme from Hevea (rubber tree) and Manihot spp. (cassava) accepts aliphatic and aromatic hydroxynitriles, unlike EC, which does not act on aliphatic hydroxynitriles. 2-Hydroxyisobutyronitrile (acetone cyanohydrin) is liberated by glycosidase action on linamarin.


1. Selmar, D., Lieberei, R., Biehl, B., Conn, E.E. α-Hydroxynitrile lyase in Hevea brasiliensis and its significance for rapid cyanogenesis. Physiol. Plant 75 (1989) 97-101.


Recommended name: tagatose-bisphosphate aldolase

Reaction: D-tagatose 1,6-bisphosphate = glycerone phosphate + D-glyceraldehyde 3-phosphate

Systematic name: D-tagatose-1,6-bisphosphate triosephosphate lyase

Comments: enzyme activity is stimulated by certain divalent cations. It is involved in the tagatose 6-phosphate pathway of lactose catabolism in bacteria.


1. Anderson, R.L., Markwell, J.P. D-Tagatose-1,6-bisphosphate aldolase (Class II) from Klebsiella pneumoniae. Methods Enzymol. 90 (1982) 323-324.

2. Van Rooijen, R.J., Van Schalkwijk, S., De Vos, W.M. Molecular cloning, characterization, and nucleotide sequence of the tagatose 6-phosphate pathway gene cluster of the lactose operon of Lactococcus lactis. J. Biol. Chem. 266 (1991) 7176-7181. [PMID: 1901863]


Recommended name: aristolochene synthase

Reaction: trans,trans-farnesyl diphosphate = aristolochene + diphosphate

Other name(s): sesquiterpene cyclase

Systematic name: trans,trans-farnesyl diphosphate aristolochene-lyase

Comments: The initial internal cyclization produces the monocyclic intermediate germacrene A; further cyclization and methyl transfer converts the intermediate into aristolochene. The enzyme from Penicillium roqueforti requires magnesium and manganese ions. Aristolochene is the likely parent compound for a number of sesquiterpenes produced by filamentous fungi.


1. Cane, D.E., Prabhakaran, P.C., Oliver, J.S., McIlwaine, D.B. Aristolochene biosynthesis. Stereochemistry of the deprotonation steps in the enzymatic cyclization of farnesyl pyrophosphate. J. Am. Chem. Soc. 112 (1990) 3209-3210.

2. Cane, D.E., Prabhakaran, P.C., Salaski, E.J., Harrison, P.M.H., Noguchi, H., Rawlings, B.J. Aristolochene biosynthesis and enzymatic cyclization of farnesyl pyrophosphate. J. Am. Chem. Soc. 111 (1989) 8914-8916.

3. Hohn, T.M., Plattner, R.D. Purification and characterization of the sesquiterpene cyclase aristolochene synthase from Penicillium roqueforti. Arch. Biochem. Biophys. 272 (1989) 137-143. [PMID: 2544140]

4. Proctor, R.H., Hohn, T.M. Aristolochene synthase. Isolation, characterization, and bacterial expression of a sesquiterpenoid biosynthetic gene (Ari1) from Penicillium roqueforti. J. Biol. Chem. 268 (1993) 4543-4548. [PMID: 8440737]


Recommended name: 4a-hydroxytetrahydrobiopterin dehydratase

Reaction: (6R)-6-(L-erythro-1,2-dihydroxypropyl)-5,6,7,8-tetrahydro-4a-hydroypterin = (6R)-6-(L-erythro-1,2-dihydroxypropyl)-7,8-dihydro-6H-pterin + H2O

Other name(s): 4α-hydroxy-tetrahydropterin dehydratase; pterin-4α-carbinolamine dehydratase

Systematic name: 4a-hydroxytetrahydrobiopterin hydro-lyase

Comments: catalyses the dehydration of 4a-hydroxytetrahydrobiopterins


1. Hauer, C.R., Rebrin, I., Thöny, B., Neuheiser, F., Curtius, H.C., Hunziker, P., Blau, N., Ghisla, S., Heizmann, C.W. Phenylalanine hydroxylase-stimulating protein: pterin-4α-carbinolamine dehydratase from rat and human liver. J. Biol. Chem. 268 (1993) 4828-4831. [PMID: 8444860]


Recommended name: phaseollidin hydratase

Reaction: phaseollidin hydrate = phaseollidin + H2O

Systematic name: phaseollidin-hydrate hydro-lyase

Comments: the enzyme from Fusarium solani, which is distinct from kievitone hydratase (EC, hydrates the methylbutenyl side-chain of the isoflavonoid phytoalexin, phaseollidin.


1. Turbek, C.S., Smith, D.A., Schardl, C.L. An extracellular enzyme from Fusarium solani f.sp. phaseoli, which catalyses hydration of the isoflavonoid phytoalexin, phaseollidin. FEMS Microbiol. Lett. 94 (1992) 187-190. [PMID: 1521768]


Recommended name: 16α-hydroxyprogesterone dehydratase

Reaction: 16α-hydroxyprogesterone = 16,17-didehydroprogesterone + H2O

Other name(s): hydroxyprogesterone dehydroxylase

Systematic name: 16α-hydroxyprogesterone hydro-lyase

Comments: 16α-hydroxypregnenolone is also a substrate.


1. Glass, T.L., Lamppa, R.S. Purification and properties of 16α-hydroxyprogesterone dehydroxylase from Eubacterium sp. strain 144. Biochim. Biophys. Acta 837 (1985) 103-110. [PMID: 4052439]


Recommended name: 2-methylisocitrate dehydratase

Reaction: (2S,3R)-3-hydroxybutane-1,2,3-tricarboxylate = (Z)-but-2-ene-1,2,3-tricarboxylate + H2O

Other name(s): (2S,3R)-3-hydroxybutane-1,2,3-tricarboxylate hydro-lyase

Systematic name: (2S,3R)-3-hydroxybutane-1,2,3-tricarboxylate hydro-lyase

Comments: the enzyme from the fungus Yarrowia lipolytica (Saccharomycopsis) does not act on isocitrate.


1. Aoki, H., Uchiyama, H., Umetsu, H., Tabuchi, T. Isolation of 2-methylisocitrate dehydratase, a new enzyme serving in the methylcitric acid cycle for propionate metabolism, from Yarrowia lipolytica. Biosci. Biotechnol. Biochem. 59 (1995) 1825-1828

2. Tabuchi, T., Umetsu, H., Aoki, H., Uchiyama, H. Characteristics of 2-methylisocitrate dehydratase, isolated from Yarrowia lipolytica, in comparison to aconitase. Biosci. Biotechnol. Biochem. 59 (1995) 2013-2017.


Recommended name: exo-(1[arrow to right]4)-α-D-glucan lyase

Reaction: linear α-glucan = glucose + 1,5-anhydro-D-fructose

Other name(s): α-(1[arrow to right]4)-glucan 1,5-anhydro-D-fructose eliminase; α-1,4-glucan exo-lyase; α-1,4-glucan lyase

Systematic name: (1[arrow to right]4)-α-D-glucan exo-4-lyase (1,5-anhydro-D-fructose-forming)

Comments: the enzyme catalyses the sequential degradation of (1[arrow to right]4)-α-D-glucans from the non-reducing end with the release of 1,5-anhydro-D-fructose. Thus, for an α-glucan containing n (1[arrow to right]4)-linked glucose units, the final products are 1 glucose plus (n-1) 1,5-anhydro-D-fructose. Maltose, maltosaccharides and amylose are all completely degraded. It does not degrade (1[arrow to right]6)-α-glucosidic bonds and thus the degradation of a branched glucan, such as amylopectin or glycogen, will result in the formation of 1,5-anhydro-D-fructose plus a limit dextrin.


1. Yu, S., Kenne, L., Pedersén, M. α-1,4-Glucan lyase, a new class of starch/glycogen degrading enzyme. I. Efficient purification and characterization from red seaweeds. Biochim. Biophys. Acta 1156 (1993) 313-320. [PMID: 8461323]

2. Yu, S., Pedersén, M. α-1,4-Glucan lyase, a new class of starch/glycogen degrading enzyme. II. Subcellular localization and partial amino-acid sequence. Planta 191 (1993) 137-142.


Recommended name: 3-aminobutyryl-CoA ammonia-lyase

Reaction: L-3-aminobutyryl-CoA = crotonoyl-CoA + NH3+

Other name(s): L-3-aminobutyryl-CoA deaminase

Systematic name: L-3-aminobutyryl-CoA ammonia-lyase

Comments: hydroxylamine can replace ammonia as a substrate. Crotonoyl-pantetheine can replace crotonoyl-CoA but it is a poorer substrate.


1. Jeng, I.-M., Barker, H.A. Purification and properties of L-3-aminobutyryl coenzyme A deaminase from a lysine-fermenting Clostridium. J. Biol. Chem. 249 (1974) 6578-6584. [PMID: 4420467]

2. Barker, H.A., Kahn, J.M., Chew, S. Enzymes involved in 3,5-diaminohexanoate degradation by Brevibacterium sp. J. Bacteriol. 143 (1980) 1165-1170. [PMID: 7410315]


Recommended name: diaminopropionate ammonia-lyase

Reaction: 2,3-diaminopropionate + H2O= pyruvate + 2 ammonia

Other name(s): diaminopropionatase; αβ-diaminopropionate ammonia-lyase

Systematic name: 2,3-diaminopropionate ammonia-lyase

Comments: a pyridoxal phosphate enzyme. Active towards both D- and L-diaminopropionate. D- and L-serine are poor substrates.


1. Nagasawa, T., Tanizawa, K., Satoda, T., Yamada, H. Diaminopropionate ammonia-lyase from Salmonella typhimurium. Purification and characterization of the crystalline enzyme, and sequence determination of the pyridoxal 5'-phosphate binding peptide. J. Biol. Chem. 263 (1988) 958-964. [PMID: 3275662]


Recommended name: 6-pyruvoyltetrahydropterin synthase

Reaction: 6-(L-erythro-1,2-dihydroxypropyl 3-triphosphate)-7,8-dihydropteridin = 6-(1,2-dioxopropyl)-5,6,7,8-tetrahydropterin + triphosphate

Systematic name: 2-amino-4-oxo-6-(erythro-1',2',3'-trihydroxypropyl)-7,8-dihydroxypterdine triphosphate lyase

Comments: catalyses triphosphate elimination and an intramolecular redox reaction in the presence of Mg2+. It has been identified in human liver. The product is 6-pyruvoyltetrahydrobiopterin.


1. Milstien, S., Kaufman, S. The biosynthesis of tetrahydrobiopterin in rat brain. Purification and characterization of 6-pyruvoyl-tetrahydrobiopterin(2'-oxo) reductase. J. Biol. Chem. 264 (1989) 8066-8073. [PMID: 2656673]

2. Thöny, B., Leimbacher, W., Bürgisser, D., Heinzmann, C.W. Human 6-pyruvoyl-tetrahydrobiopterin synthase: cDNA cloning and heterologous expression of the recombinant enzyme. Biochem. Biophys. Res. Commun. 189 (1992) 1437-1443. [PMID: 1282802]


Recommended name: (+)-δ-cadinene synthase

Reaction: 2-trans,6-trans-farnesyl diphosphate = (+)-δ-cadinene + diphosphate

Systematic name: 2-trans,6-trans-farnesyl-diphosphate diphosphate-lyase (cyclizing, (+)-δ-cadinene-forming)

Comments: the sesquiterpenoid (+)-δ-cadinene is an intermediate in phytoalexin biosynthesis. Mg2+ is required for activity.


1. Davis, G.D., Essenberg, M. (+)-δ-Cadinene is a product of sesquiterpene cyclase activity in cotton. Phytochemistry 39 (1995) 553-567.

2. Chen, X.-Y., Chen, Y., Heinstein, P., Davisson, V.J. Cloning, expression and characterization of (+)-δ-cadinene synthase: a catalyst for cotton phytoalexin biosynthesis. Arch. Biochem. Biophys. 324 (1995) 255-266. [PMID: 8554317]

3. Davis, E.M., Tsuji, J., Davis, G.D., Pierce, M.L., Essenberg, M. Purification of (+)-δ-cadinene synthase, a sesquiterpene cyclase from bacteria-inoculated cotton foliar tissue. Phytochemistry 41 (1996) 1047-1055.



Recommended name: sulfinoalanine decarboxylase

Reaction: 3-sulfino-L-alanine = hypotaurine + CO2

Other names: cysteine-sulfinate decarboxylase

Systematic name: 3-sulfino-L-alanine carboxy-lyase

Comments: a pyridoxal-phosphate protein. Also acts on L-cysteate. The 1992 edition of the Enzyme List erroneously gave the name sulfoalanine decarboxylase to this enzyme.


1. Guion-Rain, M.C., Portemer, C., Chatagner, F. Rat liver cysteine sulfinate decarboxylase: purification, new appraisal of molecular weight and determination of catalytic properties. Biochim. Biophys. Acta 384 (1975) 265-276. [PMID: 236774]

2. Jacobsen, J.G., Thomas, L.L., Smith, L.H., Jr. Properties and distribution of L-cysteine sulfinate carboxy-lyase. Biochim. Biophys. Acta 85 (1964) 103-116.


Recommended name: mandelonitrile lyase

Reaction: mandelonitrile = cyanide + benzaldehyde

Other name(s): hydroxynitrile lyase; (R)-oxynitrilase

Systematic name: mandelonitrile benzaldehyde-lyase

Comments: a variety of enzymes from different sources and with different properties. Some are flavoproteins, others are not. Active towards a number of aromatic and aliphatic hydroxynitriles (cyanohydrins).


1. Becker, W., Benthin, U., Eschenhof, E., Pfeil, E. [Cyanohydrin synthesis. II. Purification and properties of oxynitrilase of bitter almonds (Prunus communis).] [German] Biochem. Z. 337 (1963) 156-166.

2. Becker, W., Pfeil, E. Die Darstellung kristallisierter Oxynitrilase aus bitteren Mandeln (Prunus comm. Stks). Naturwissenschaften 51 (1964) 193.

3. Gross, M., Jacobs, G.H., Poulton, J.E. A rapid and sensitive spectrophotometric assay for prunasin hydrolase activity employing purified mandelonitrile lyase. Anal. Biochem. 119 (1982) 25-30. [PMID: 6803611]

4. Xu, L.-L., Singh, B.K., Conn, E.E. Purification and characterization of mandelonitrile lyase from Prunus lyonii. Arch. Biochem. Biophys. 250 (1986) 322-328. [PMID: 3777939]

5. Yemm, R.S., Poulton, J.E. Isolation and characterization of multiple forms of mandelonitrile lyase from mature black cherry (Prunus serotina Ehrh.) seeds. Arch. Biochem. Biophys. 247 (1986) 440-445. [PMID: 3717954]


Recommended name: hydroxymandelonitrile lyase

Reaction: (S)-4-hydroxymandelonitrile = cyanide + 4-hydroxybenzaldehyde

Other name(s): hydroxynitrile lyase

Systematic name: (S)-4-hydroxymandelonitrile hydroxybenzaldehyde-lyase

Comments: does not accept aliphatic hydroxynitriles, unlike EC and


1. Bové, C., Conn, E.E. Metabolism of aromatic compounds in higher plants. II. Purification and properties of the oxynitrilase of Sorghum vulgare. J. Biol. Chem. 236 (1961) 207-210.

2. Seely, M.K., Criddle, R.S., Conn, E.E. The metabolism of aromatic compounds in higher plants. 8. On the requirement of hydroxynitrile lyase for flavin. J. Biol. Chem. 241 (1966) 4457-4462. [PMID: 5922969]


Recommended name: fructose-bisphosphate aldolase

Reaction: D-fructose 1,6-bisphosphate = glycerone phosphate + D-glyceraldehyde 3-phosphate

Other name(s): aldolase; fructose-1,6-bisphosphate triosephosphate-lyase

Systematic name: D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate-lyase

Comments: also acts on (3S,4R)-ketose 1-phosphates. The yeast and bacterial enzymes are zinc proteins. The enzymes increase electron-attraction by the carbonyl group, some (Class I) forming a protonated imine with it, others (Class II), mainly of microbial origin, polarizing it with a metal ion, e.g. zinc.


1. Horecker, B.L., Tsolas, O.and Lai, C.Y. Aldolases. In Boyer, P.D., (Ed.) The Enzymes, 3rd ed., vol.7, p.213, Academic Press, New York, 1972, p. 213-25.

2. Alefounder, P.R., Baldwin, S.A., Perham, R.N., Short, N.J. Cloning, sequence analysis and over-expression of the gene for the class II fructose 1,6-bisphosphate aldolase of Escherichia coli. Biochem. J. 257 (1989) 529-534. [PMID: 2649077]


Recommended name: (S)-norcoclaurine synthase

Reaction: 4-(2-aminoethyl)benzene-1,2-diol + 4-hydroxyphenylacetaldehyde = (S)-norcoclaurine + H2O

Other name(s): (S)-norlaudanosoline synthase

Systematic name: 4-hydroxyphenylacetaldehyde hydro-lyase (adding dopamine)

Comments: the reaction makes a six-membered ring by forming a bond between C-6 of the 3,4-dihydroxyphenyl group of the dopamine and C-1 of the aldehyde in the imine formed between the substrates. The product is the precursor of the benzylisoquinoline alkaloids in plants. The enzyme, formerly known as (S)-norlaudanosoline synthase, will also catalyse the reaction of 4-(2-aminoethyl)benzene-1,2-diol + (3,4-dihydroxyphenyl)acetaldehyde to form (S)-norlaudanosoline, but this alkaloid has not been found to occur in plants.


1. Stadler, R., Zenk, M.H. A revision of the generally accepted pathway for the biosynthesis of the benzotetrahydroisoquinoline reticuline. Liebigs Ann. Chem. (1990) 555-562.

2. Stadler, R., Kutchan, T.M., Zenk, M.H. (S)-Norcoclaurine is the central intermediate in benzylisoquinoline alkaloid biosynthesis. Phytochemistry 28 (1989) 1083-1086.

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