Accepted name: trans-feruloyl-CoA hydratase
Reaction: 4-hydroxy-3-methoxyphenyl-β-hydroxypropanoyl-CoA = feruloyl-CoA + H2O =
Other name(s): trans-feruloyl-CoA hydro-lyase (incorrect); 4-hydroxy-3-methoxyphenyl-β-hydroxypropanoyl-CoA hydro-lyase (trans-feruloyl-CoA-forming)
Systematic name: 4-hydroxy-3-methoxyphenyl-β-hydroxypropanoyl-CoA hydro-lyase (feruloyl-CoA-forming)
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 197462-62-7
References:
1. Narbad, A. and Gasson, M.J. Metabolism of ferulic acid via vanillin using a novel CoA-dependent pathway in a newly-isolated strain of Pseudomonas fluorescens. Microbiology 144 (1998) 1397-1405. [PMID: 9611814]
2. Pometto, A.L. and Crawford, D.L. Whole-cell bioconversion of vanillin to vanillic acid by Streptomyces viridosporus. Appl. Environ. Microbiol. 45 (1983) 1582-1585. [PMID: 6870241]
[EC 4.2.1.102 Transferred entry: now EC 4.2.1.100 cyclohexa-1,5-diene-1-carbonyl-CoA hydratase (EC 4.2.1.102 created 2001, deleted 2001)]
Accepted name: cyclohexyl-isocyanide hydratase
Reaction: N-cyclohexylformamide = cyclohexyl isocyanide + H2O
Other name(s): isonitrile hydratase; N-cyclohexylformamide hydro-lyase
Systematic name: N-cyclohexylformamide hydro-lyase (cyclohexyl-isocyanide-forming)
Comments: The enzyme from Pseudomonas putida strain N19-2 can also catalyse the hydration of other isonitriles to the corresponding N-substituted formamides. The enzyme has no metal requirements.
Links to other databases: BRENDA, EXPASY, KEGG, UM-BBD, CAS registry number: 358974-06-8
References:
1. Goda, M., Hashimoto, Y., Shimizu, S. and Kobayashi, M. Discovery of a novel enzyme, isonitrile hydratase, involved in nitrogen-carbon triple bond cleavage. J. Biol. Chem. 276 (2001) 23480-23485. [PMID: 11306561]
Accepted name: cyanase
Reaction: cyanate + HCO3- + 2 H+ = NH3 + 2 CO2 (overall reaction)
(1a) cyanate + HCO3- + H+ = carbamate + CO2
(1b) carbamate + H+ = NH3 + CO2 (spontaneous)
For diagram click here.
Glossary: cyanate = NCO-
carbamate = H2N-CO-O-
Other name(s): cyanate lyase; cyanate hydrolase; cyanase; cyanate aminohydrolase; cyanate C-N-lyase; cyanate hydratase
Systematic name: carbamate hydro-lyase
Comments: This enzyme, which is found in bacteria and plants, is used to decompose cyanate, which can be used as the sole source of nitrogen [6,7]. Reaction (1) can be considered as the reverse of 'carbamate = cyanate + H2O', where this is assisted by reaction with bicarbonate and carbon dioxide (see mechanism above) [2], and hence is classified in sub-subclass 4.2.1. Bicarbonate functions as a recycling substrate [2].
Links to other databases: BRENDA, EXPASY, KEGG, PDB, UM-BBD, CAS registry number: 37289-24-0
References:
1. Anderson, P.M. Purification and properties of the inducible enzyme cyanase. Biochemistry 19 (1980) 2882-2888. [PMID: 6994799]
2. Johnson, W.V. and Anderson, P.M. Bicarbonate is a recycling substrate for cyanase. J. Biol. Chem. 262 (1987) 9021-9025. [PMID: 3110153]
3. Taussig, A. The synthesis of the induced enzyme, "cyanase", in E. coli. Biochim. Biophys. Acta 44 (1960) 510-519. [PMID: 13775509]
4. Taussig, A. Some properties of the induced enzyme cyanase. Can. J. Biochem. 43 (1965) 1063-1069. [PMID: 5322950]
5. Anderson, P.M., Korte, J.J. and Holcomb, T.A. Reaction of the N-terminal methionine residues in cyanase with diethylpyrocarbonate. Biochemistry 33 (1994) 14121-14125. [PMID: 7947823]
6. Kozliak, E.I., Fuchs, J.A., Guilloton, M.B. and Anderson, P.M. Role of bicarbonate/CO2 in the inhibition of Escherichia coli growth by cyanate. J. Bacteriol. 177 (1995) 3213-3219. [PMID: 7768821]
7. Walsh, M.A., Otwinowski, Z., Perrakis, A., Anderson, P.M. and Joachimiak, A. Structure of cyanase reveals that a novel dimeric and decameric arrangement of subunits is required for formation of the enzyme active site. Structure 8 (2000) 505-514. [PMID: 10801492]
Accepted name: 2-hydroxyisoflavanone dehydratase
Reaction: 2,7,4'-trihydroxyisoflavanone = daidzein + H2O
See diagram for reaction in genistein or daidzein biosynthesis.
Glossary: daidzein = 7,4'-dihydroxyisoflavone
Other name(s): 2,7,4′-trihydroxyisoflavanone hydro-lyase
Systematic name: 2,7,4′-trihydroxyisoflavanone hydro-lyase (daidzein-forming)
Comments: Catalyses the final step in the formation of the isoflavonoid skeleton. The reaction also occurs spontaneously.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 166800-10-8
References:
1. Hakamatsuka, T., Mori, K., Ishida, S., Ebizuka, Y and Sankawa, U. Purification of 2-hydroxyisoflavanone dehydratase from the cell cultures of Pueraria lobata. Phytochemistry 49 (1998) 497-505.
Accepted name: bile-acid 7α-dehydratase
Reaction: 7α,12α-dihydroxy-3-oxochol-4-enoate = 12α-hydroxy-3-oxochola-4,6-dienoate + H2O
For diagram click here.
Other name(s): 7α,12α-dihydroxy-3-oxochol-4-enoate hydro-lyase
Systematic name: 7α,12α-dihydroxy-3-oxochol-4-enoate hydro-lyase (12α-hydroxy-3-oxochola-4,6-dienoate-forming)
Comments: The enzyme from Eubacterium sp. strain VPI 12708 can also use 7α-hydroxy-3-oxochol-4-enoate as a substrate but not 7α,12α-dihydroxy-3-oxochol-5β-anoate, 3α,7α,12α-trihydroxychol-5β-anoate or 7β-hydroxy-3-oxochol-4-enoate.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Dawson, J.A., Mallonee, D.H., Björkhem, I. and Hylemon, P.B. Expression and characterization of a C24 bile acid 7α-dehydratase from Eubacterium sp. strain VPI 12708 in Escherichia coli. J. Lipid Res. 37 (1996) 1258-1267. [PMID: 8808760]
Accepted name: 3α,7α,12α-trihydroxy-5β-cholest-24-enoyl-CoA hydratase
Reaction: (24R,25R)-3α,7α,12α,24-tetrahydroxy-5β-cholestanoyl-CoA = (24E)-3α,7α,12α-trihydroxy-5β-cholest-24-enoyl-CoA + H2O
For diagram click here.
Other name(s): 46 kDa hydratase 2; (24R,25R)-3α,7α,12α,24-tetrahydroxy-5β-cholestanoyl-CoA hydro-lyase
Systematic name: (24R,25R)-3α,7α,12α,24-tetrahydroxy-5β-cholestanoyl-CoA hydro-lyase [(24E)-3α,7α,12α-trihydroxy-5β-cholest-24-enoyl-CoA-forming]
Comments: This enzyme forms part of the rat peroxisomal multifunctional enzyme perMFE-2, which also exhibits a dehydrogenase activity. The enzyme is involved in the β-oxidation of the cholesterol side chain in the cholic-acid-biosynthesis pathway.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 152787-68-3
References:
1. Qin, Y.M., Haapalainen, A.M., Conry, D., Cuebas, D.A., Hiltunen, J.K. and Novikov, D.K. Recombinant 2-enoyl-CoA hydratase derived from rat peroxisomal multifunctional enzyme 2: role of the hydratase reaction in bile acid synthesis. Biochem. J. 328 (1997) 377-382. [PMID: 9371691]
2. Xu, R. and Cuebas, D.A. The reactions catalyzed by the inducible bifunctional enzyme of rat liver peroxisomes cannot lead to the formation of bile acids. Biochem. Biophys. Res. Commun. 221 (1996) 271-278. [PMID: 8619845]
3. Kinoshita, T., Miyata, M., Ismail, S.M., Fujimoto, Y., Kakinuma, K., Kokawa, N.I. and Morisaki, M. Synthesis and determination of stereochemistry of four diastereoisomers at the C-24 and C-25 positions of 3α,7α,12α,24-tetrahydroxy-5β-cholestan-26-oic acid and cholic acid. Chem. Pharm. Bull. 36 (1988) 134-141.
4. Fujimoto, Y., Kinoshita, T., Oya, I., Kakinuma, K., Ismail, S.M., Sonoda, Y., Sato, Y. and Morisaki, M. Non-stereoselective conversion of the four diastereoisomers at the C-24 and C-25 positions of 3α,7α,12α,24-tetrahydroxy-5β-cholestan-26-oic acid and cholic acid. Chem. Pharm. Bull. 36 (1988) 142-145.
5. Kurosawa, T., Sato, M., Nakano, H., Fujiwara, M., Murai, T., Yoshimura, T. and Hashimoto, T. Conjugation reactions catalyzed by bifunctional proteins related to β-oxidation in bile acid biosynthesis. Steroids 66 (2001) 107-114. [PMID: 11146090]
6. Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137-174. [PMID: 12543708]
Accepted name: ectoine synthase
Reaction: N4-acetyl-L-2,4-diaminobutanoate = L-ectoine + H2O
For diagram, click here
Glossary: ectoine = (4S)-2-methyl-1,4,5,6-tetrahydropyrimidine-4-carboxylate
Other name(s): N-acetyldiaminobutyrate dehydratase; N-acetyldiaminobutanoate dehydratase; L-ectoine synthase; EctC; N4-acetyl-L-2,4-diaminobutanoate hydro-lyase; 4-N-acetyl-L-2,4-diaminobutanoate hydro-lyase; 4-N-acetyl-L-2,4-diaminobutanoate hydro-lyase (L-ectoine-forming)
Systematic name: N4-acetyl-L-2,4-diaminobutanoate hydro-lyase (L-ectoine-forming)
Comments: Ectoine is an osmoprotectant that is found in halophilic eubacteria. This is the third enzyme in the ectoine-biosynthesis pathway, the other enzymes involved being EC 2.6.1.76, diaminobutyrate—2-oxoglutarate transaminase and EC 2.3.1.178, diaminobutyrate acetyltransferase [1,2].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Peters, P., Galinski, E.A. and Truper, H.G. The biosynthesis of ectoine. FEMS Microbiol. Lett. 71 (1990) 157-162.
2. Ono, H., Sawada, K., Khunajakr, N., Tao, T., Yamamoto, M., Hiramoto, M., Shinmyo, A., Takano, M. and Murooka, Y. Characterization of biosynthetic enzymes for ectoine as a compatible solute in a moderately halophilic eubacterium, Halomonas elongata. J. Bacteriol. 181 (1999) 91-99. [PMID: 9864317]
3. Kuhlmann, A.U. and Bremer, E. Osmotically regulated synthesis of the compatible solute ectoine in Bacillus pasteurii and related Bacillus spp. Appl. Environ. Microbiol. 68 (2002) 772-783. [PMID: 11823218]
4. Louis, P. and Galinski, E.A. Characterization of genes for the biosynthesis of the compatible solute ectoine from Marinococcus halophilus and osmoregulated expression in Escherichia coli. Microbiology 143 (1997) 1141-1149. [PMID: 9141677]
Accepted name: methylthioribulose 1-phosphate dehydratase
Reaction: S-methyl-5-thio-D-ribulose 1-phosphate = 5-(methylthio)-2,3-dioxopentyl phosphate + H2O
For diagram click here.
Other name(s): 1-PMT-ribulose dehydratase; S-methyl-5-thio-D-ribulose-1-phosphate hydro-lyase
Systematic name: S-methyl-5-thio-D-ribulose-1-phosphate 4-hydro-lyase [5-(methylthio)-2,3-dioxopentyl-phosphate-forming]
Comments: This enzyme forms part of the methionine-salvage pathway.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 1114239-22-3
References:
1. Furfine, E.S. and Abeles, R.H. Intermediates in the conversion of 5'-S-methylthioadenosine to methionine in Klebsiella pneumoniae. J. Biol. Chem. 263 (1988) 9598-9606. [PMID: 2838472]
2. Wray, J.W. and Abeles, R.H. The methionine salvage pathway in Klebsiella pneumoniae and rat liver. Identification and characterization of two novel dioxygenases. J. Biol. Chem. 270 (1995) 3147-3153. [PMID: 7852397]
Accepted name: aldos-2-ulose dehydratase
Reaction: 1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one
+ H2O (overall reaction)
(1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O
(1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one
For diagram click here.
Glossary: 1,5-anhydro-D-fructose = 1,5-anhydro-D-arabino-hex-2-ulose = (4S,5S,6R)-4,5-dihydroxy-6-(hydroxymethyl)dihydro-2H-pyran-3(4H)-one
ascopyrone M = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = (6S)-4-hydroxy-6-(hydroxymethyl)-2H-pyran-3(6H)-one
microthecin = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one
Other name(s): pyranosone dehydratase; AUDH; 1,5-anhydro-D-fructose dehydratase (microthecin-forming)
Systematic name: 1,5-anhydro-D-fructose hydro-lyase (microthecin-forming)
Comments: This enzyme catalyses two of the steps in the anhydrofructose pathway, which leads to the degradation of glycogen and starch via 1,5-anhydro-D-fructose [1,2]. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1→4)-α-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). Aldose-2-uloses such as 2-dehydroglucose can also act as substrates, but more slowly [1,2,4]. This is a bifunctional enzyme that acts as both a lyase and as an isomerase [2]. Differs from EC 4.2.1.111, which can carry out only reaction (1a) and requires a cofactor for activity [5].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 101920-80-3
References:
1. Yu, S. and Fiskesund, R. The anhydrofructose pathway and its possible role in stress response and signaling. Biochim. Biophys. Acta 1760 (2006) 1314-1322. [PMID: 16822618]
2. Yu, S. Enzymatic description of the anhydrofructose pathway of glycogen degradation. II. Gene identification and characterization of the reactions catalyzed by aldos-2-ulose dehydratase that converts 1,5-anhydro-D-fructose to microthecin with ascopyrone M as the intermediate. Biochim. Biophys. Acta 1723 (2005) 63-73. [PMID: 15716041]
3. Broberg, A., Kenne, L. and Pedersén, M. Presence of microthecin in the red alga Gracilariopsis lemaneiformis and its formation from 1,5-anhydro-D-fructose. Phytochemistry 41 (1996) 151-154.
4. Gabriel, J., Volc, J., Sedmera, P., Daniel, G. and Kubátová, E. Pyranosone dehydratase from the basidiomycete Phanerochaete chrysosporium: improved purification, and identification of 6-deoxy-D-glucosone and D-xylosone reaction products. Arch. Microbiol. 160 (1993) 27-34. [PMID: 8352649]
5. Yu, S., Refdahl, C. and Lundt, I. Enzymatic description of the anhydrofructose pathway of glycogen degradation; I. Identification and purification of anhydrofructose dehydratase, ascopyrone tautomerase and α-1,4-glucan lyase in the fungus Anthracobia melaloma. Biochim. Biophys. Acta 1672 (2004) 120-129. [PMID: 15110094]
Accepted name: 1,5-anhydro-D-fructose dehydratase
Reaction: 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O
For diagram click here.
Glossary: 1,5-anhydro-D-fructose = 1,5-anhydro-D-arabino-hex-2-ulose = (4S,5S,6R)-4,5-dihydroxy-6-(hydroxymethyl)dihydro-2H-pyran-3(4H)-one
ascopyrone M = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = (6S)-4-hydroxy-6-(hydroxymethyl)-2H-pyran-3(6H)-one
ascopyrone M = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 4-hydroxy-6-(hydroxymethyl)-2H-pyran-3(6H)-one
Other name(s): 1,5-anhydro-D-fructose 4-dehydratase; 1,5-anhydro-D-fructose hydrolyase; 1,5-anhydro-D-arabino-hex-2-ulose dehydratase; AFDH; AF dehydratase; 1,5-anhydro-D-fructose hydro-lyase
Systematic name: 1,5-anhydro-D-fructose hydro-lyase (ascopyrone-M-forming)
Comments: This enzyme catalyses one of the steps in the anhydrofructose pathway, which leads to the degradation of glycogen and starch via 1,5-anhydro-D-fructose [1,2]. The other enzymes involved in this pathway are EC 4.2.1.110 (aldos-2-ulose dehydratase), EC 4.2.2.13 [exo-(1→4)-α-D-glucan lyase] and EC 5.3.3.15 (ascopyrone tautomerase). Requires divalent (Ca2+ or Mg2+) or monovalent cations (Na+) for optimal activity. Unlike EC 4.2.1.110, aldos-2-ulose dehydratase, the enzyme is specific for 1,5-anhydro-D-fructose as substrate and shows no activity towards aldose-2-uloses such as 2-dehydroglucose [1,2,3]. In addition, it is inhibited by its end-product ascopyrone M [2] and it cannot convert ascopyrone M into microthecin, as can EC 4.2.1.110.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Yu, S., Refdahl, C. and Lundt, I. Enzymatic description of the anhydrofructose pathway of glycogen degradation; I. Identification and purification of anhydrofructose dehydratase, ascopyrone tautomerase and α-1,4-glucan lyase in the fungus Anthracobia melaloma. Biochim. Biophys. Acta 1672 (2004) 120-129. [PMID: 15110094]
2. Yu, S. and Fiskesund, R. The anhydrofructose pathway and its possible role in stress response and signaling. Biochim. Biophys. Acta 1760 (2006) 1314-1322. [PMID: 16822618]
3. Yu, S. Enzymatic description of the anhydrofructose pathway of glycogen degradation. II. Gene identification and characterization of the reactions catalyzed by aldos-2-ulose dehydratase that converts 1,5-anhydro-D-fructose to microthecin with ascopyrone M as the intermediate. Biochim. Biophys. Acta 1723 (2005) 63-73. [PMID: 15716041]
Accepted name: acetylene hydratase
Reaction: acetaldehyde = acetylene + H2O
Other name(s): AH; acetaldehyde hydro-lyase
Systematic name: acetaldehyde hydro-lyase (acetylene-forming)
Comments: This is a non-redox-active enzyme that contains two molybdopterin guanine dinucleotide (MGD) cofactors, a tungsten centre and a cubane type [4Fe-4S] cluster [2]. The tungsten centre binds a water molecule that is activated by an adjacent aspartate residue, enabling it to attack acetylene bound in a distinct hydrophobic pocket [2]. Ethylene cannot act as a substrate [1].
Links to other databases: BRENDA, EXPASY, KEGG, UM-BBD, CAS registry number: 75788-81-7
References:
1. Rosner, B.M. and Schink, B. Purification and characterization of acetylene hydratase of Pelobacter acetylenicus, a tungsten iron-sulfur protein. J. Bacteriol. 177 (1995) 5767-5772. [PMID: 7592321]
2. Seiffert, G.B., Ullmann, G.M., Messerschmidt, A., Schink, B., Kroneck, P.M. and Einsle, O. Structure of the non-redox-active tungsten/[4Fe:4S] enzyme acetylene hydratase. Proc. Natl. Acad. Sci. USA 104 (2007) 3073-3077. [PMID: 17360611]
Accepted name: o-succinylbenzoate synthase
Reaction: (1R,6R)-6-hydroxy-2-succinylcyclohexa-2,4-diene-1-carboxylate = 2-succinylbenzoate + H2O
For diagram click here.
Glossary: 2-succinylbenzoate = o-succinylbenzoate = 4-(2-carboxyphenyl)-4-oxobutanoate
Other name(s): o-succinylbenzoic acid synthase; OSB synthase; OSBS; 2-succinylbenzoate synthase; MenC
Systematic name: (1R,6R)-6-hydroxy-2-succinylcyclohexa-2,4-diene-1-carboxylate hydrolyase (2-succinylbenzoate-forming)
Comments: Belongs to the enolase superfamily and requires divalent cations, preferably Mg2+ or Mn2+, for activity. Forms part of the vitamin-K-biosynthesis pathway.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Sharma, V., Meganathan, R. and Hudspeth, M.E. Menaquinone (vitamin K2) biosynthesis: cloning, nucleotide sequence, and expression of the menC gene from Escherichia coli. J. Bacteriol. 175 (1993) 4917-4921. [PMID: 8335646]
2. Klenchin, V.A., Taylor Ringia, E.A., Gerlt, J.A. and Rayment, I. Evolution of enzymatic activity in the enolase superfamily: structural and mutagenic studies of the mechanism of the reaction catalyzed by o-succinylbenzoate synthase from Escherichia coli. Biochemistry 42 (2003) 14427-14433. [PMID: 14661953]
3. Palmer, D.R., Garrett, J.B., Sharma, V., Meganathan, R., Babbitt, P.C. and Gerlt, J.A. Unexpected divergence of enzyme function and sequence: "N-acylamino acid racemase" is o-succinylbenzoate synthase. Biochemistry 38 (1999) 4252-4258. [PMID: 10194342]
4. Thompson, T.B., Garrett, J.B., Taylor, E.A., Meganathan, R., Gerlt, J.A. and Rayment, I. Evolution of enzymatic activity in the enolase superfamily: structure of o-succinylbenzoate synthase from Escherichia coli in complex with Mg2+ and o-succinylbenzoate. Biochemistry 39 (2000) 10662-10676. [PMID: 10978150]
5. Taylor Ringia, E.A., Garrett, J.B., Thoden, J.B., Holden, H.M., Rayment, I. and Gerlt, J.A. Evolution of enzymatic activity in the enolase superfamily: functional studies of the promiscuous o-succinylbenzoate synthase from Amycolatopsis. Biochemistry 43 (2004) 224-229. [PMID: 14705949]
Accepted name: methanogen homoaconitase
Reaction: (R)-2-hydroxybutane-1,2,4-tricarboxylate + H2O = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate (overall reaction)
(1a) (R)-2-hydroxybutane-1,2,4-tricarboxylate = (Z)-but-1-ene-1,2,4-tricarboxylate + H2O
(1b) (Z)-but-1-ene-1,2,4-tricarboxylate + H2O = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
Glossary: cis-homoaconitate = (Z)-but-1-ene-1,2,4-tricarboxylate
(R)-homocitrate = (R)-2-hydroxybutane-1,2,4-tricarboxylate
homoisocitrate = (–)-threo-homoisocitrate = (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate
Other name(s): methanogen HACN
Systematic name: (R)-2-hydroxybutane-1,2,4-tricarboxylate hydro-lyase [(1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate-forming]
Comments: This enzyme catalyses several reactions in the pathway of coenzyme-B biosynthesis in methanogenic archaea. Requires a [4Fe-4S] cluster for activity. In contrast to EC 4.2.1.36, homoaconitate hydratase, this enzyme can catalyse both the dehydration of (R)-homocitrate to form cis-homoaconitate and the subsequent hydration reaction that forms homoisocitrate. In addition to cis-homoaconitate, the enzyme can also catalyse the hydration of the physiological substrates dihomocitrate and trihomocitrate as well as the non-physiological substrate tetrahomocitrate. cis-Aconitate and threo-DL-isocitrate cannot act as substrates, and (S)-homocitrate and trans-homoaconitate act as inhibitors of the enzyme.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Drevland, R.M., Jia, Y., Palmer, D.R. and Graham, D.E. Methanogen homoaconitase catalyzes both hydrolyase reactions in coenzyme B biosynthesis. J. Biol. Chem. 283 (2008) 28888-28896. [PMID: 18765671]
Accepted name: UDP-N-acetylglucosamine 4,6-dehydratase (inverting)
Reaction: UDP-N-acetylglucosamine = UDP-2-acetamido-2,6-dideoxy-β-L-arabino-hex-4-ulose + H2O
Glossary: pseudaminic acid = 5,7-bis(acetylamino)-3,5,7,9-tetradeoxy-L-glycero-α-L-manno-2-nonulopyranosonic acid
Other name(s): FlaA1
Systematic name: UDP-N-acetylglucosamine hydro-lyase (inverting; UDP-2-acetamido-2,6-dideoxy-β-L-arabino-hex-4-ulose-forming)
Comments: Contains NADP+ as a cofactor. This is the first enzyme in the biosynthetic pathway of pseudaminic acid [3], a sialic-acid-like sugar that is unique to bacteria and is used by Helicobacter pylori to modify its flagellin. This enzyme plays a critical role in H. pylori's pathogenesis, being involved in the synthesis of both functional flagella and lipopolysaccharides [1,2]. It is completely inhibited by UDP-galactose. The reaction results in the chirality of the C-5 atom being inverted. It is thought that Lys-133 acts sequentially as a catalytic acid, protonating the C-6 hydroxy group and as a catalytic base, abstracting the C-5 proton, resulting in the elimination of water. This enzyme belongs to the short-chain dehydrogenase/reductase family of enzymes.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Ishiyama, N., Creuzenet, C., Miller, W.L., Demendi, M., Anderson, E.M., Harauz, G., Lam, J.S. and Berghuis, A.M. Structural studies of FlaA1 from Helicobacter pylori reveal the mechanism for inverting 4,6-dehydratase activity. J. Biol. Chem. 281 (2006) 24489-24495. [PMID: 16651261]
2. Schirm, M., Soo, E.C., Aubry, A.J., Austin, J., Thibault, P. and Logan, S.M. Structural, genetic and functional characterization of the flagellin glycosylation process in Helicobacter pylori. Mol. Microbiol. 48 (2003) 1579-1592. [PMID: 12791140]
3. Schoenhofen, I.C., McNally, D.J., Brisson, J.R. and Logan, S.M. Elucidation of the CMP-pseudaminic acid pathway in Helicobacter pylori: synthesis from UDP-N-acetylglucosamine by a single enzymatic reaction. Glycobiology 16 (2006) 8C-14C. [PMID: 16751642]
Accepted name: 3-hydroxypropionyl-CoA dehydratase
Reaction: 3-hydroxypropanoyl-CoA = acrylyl-CoA + H2O
Glossary: acrylyl-CoA = acryloyl-CoA
3-hydroxypropionyl-CoA = 3-hydroxypropanoyl-CoA
Systematic name: 3-hydroxypropionyl-CoA hydro-lyase
Comments: Catalyses a step in the 3-hydroxypropionate/4-hydroxybutyrate cycle, an autotrophic CO2 fixation pathway found in some thermoacidophilic archaea [1]. The enzyme from Metallosphaera sedula acts nearly equally as well on (S)-3-hydroxybutanoyl-CoA but not (R)-3-hydroxybutanoyl-CoA [2].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Berg, I.A., Kockelkorn, D., Buckel, W. and Fuchs, G. A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea. Science 318 (2007) 1782-1786. [PMID: 18079405]
2. Teufel, R., Kung, J.W., Kockelkorn, D., Alber, B.E. and Fuchs, G. 3-hydroxypropionyl-coenzyme A dehydratase and acryloyl-coenzyme A reductase, enzymes of the autotrophic 3-hydroxypropionate/4-hydroxybutyrate cycle in the Sulfolobales. J. Bacteriol. 191 (2009) 4572-4581. [PMID: 19429610]
Accepted name: 2-methylcitrate dehydratase (2-methyl-trans-aconitate forming)
Reaction: (2S,3S)-2-methylcitrate = 2-methyl-trans-aconitate + H2O
Glossary: (2S,3S)-2-methylcitrate = (2S,3S)-2-hydroxybutane-1,2,3-tricarboxylate
2-methyl-trans-aconitate = (2E)-but-2-ene-1,2,3-tricarboxylate
Systematic name: (2S,3S)-2-hydroxybutane-1,2,3-tricarboxylate hydro-lyase (2-methyl-trans-aconitate forming)
Comments: Catalyses the dehydration of (2S,3S)-2-methylcitrate, forming the trans isomer of 2-methyl-aconitate (unlike EC 4.2.1.79, which forms only the cis isomer). Part of a propionate degradation pathway. The enzyme from Shewanella oneidensis can also accept citrate and cis-aconitate, but activity with (2S,3S)-2-methylcitrate was approximately 2.5-fold higher. 2-methylisocitrate and isocitrate were not substrates [1]. An iron-sulfur protein.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Grimek, T.L. and Escalante-Semerena, J.C. The acnD genes of Shewenella oneidensis and Vibrio cholerae encode a new Fe/S-dependent 2-methylcitrate dehydratase enzyme that requires prpF function in vivo. J. Bacteriol. 186 (2004) 454-462. [PMID: 14702315]
Accepted name: 3-dehydroshikimate dehydratase
Reaction: 3-dehydro-shikimate = protocatechuate + H2O
Systematic name: 3-dehydroshikimate hydro-lyase
Comments: Catalyses an early step in the biosynthesis of petrobactin, a siderophore produced by many bacteria, including the human pathogen Bacillus anthracis. Requires divalent ions, with a preference for Mn2+.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Fox, D.T., Hotta, K., Kim, C.Y. and Koppisch, A.T. The missing link in petrobactin biosynthesis: asbF encodes a (–)-3-dehydroshikimate dehydratase. Biochemistry 47 (2008) 12251-12253. [PMID: 18975921]
2. Pfleger, B.F., Kim, Y., Nusca, T.D., Maltseva, N., Lee, J.Y., Rath, C.M., Scaglione, J.B., Janes, B.K., Anderson, E.C., Bergman, N.H., Hanna, P.C., Joachimiak, A. and Sherman, D.H. Structural and functional analysis of AsbF: origin of the stealth 3,4-dihydroxybenzoic acid subunit for petrobactin biosynthesis. Proc. Natl. Acad. Sci. USA 105 (2008) 17133-17138. [PMID: 18955706]
Accepted name: enoyl-CoA hydratase 2
Reaction: (3R)-3-hydroxyacyl-CoA = (2E)-2-enoyl-CoA + H2O
Other name(s): 2-enoyl-CoA hydratase 2; AtECH2; ECH2; MaoC; MFE-2; PhaJAc; D-3-hydroxyacyl-CoA hydro-lyase; D-specific 2-trans-enoyl-CoA hydratase
Systematic name: (3R)-3-hydroxyacyl-CoA hydro-lyase
Comments: This enzyme catalyses a hydration step in peroxisomal β-oxidation. The human multifunctional enzyme type 2 (MFE-2) is a 79000 Da enzyme composed of three functional units: (3R)-hydroxyacyl-CoA dehydrogenase, 2-enoyl-CoA hydratase 2 and sterol carrier protein 2-like units [1]. The enzymes from Aeromonas caviae [4] and Arabidopsis thaliana [5] are monofunctional enzymes. 2-Enoyl-CoA hydratase 3 from Candida tropicalis is a part from multifunctional enzyme type 2 [3].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Koski, K.M., Haapalainen, A.M., Hiltunen, J.K. and Glumoff, T. Crystal structure of 2-enoyl-CoA hydratase 2 from human peroxisomal multifunctional enzyme type 2. J. Mol. Biol. 345 (2005) 1157-1169. [PMID: 15644212]
2. Fukui, T., Shiomi, N. and Doi, Y. Expression and characterization of (R)-specific enoyl coenzyme A hydratase involved in polyhydroxyalkanoate biosynthesis by Aeromonas caviae. J. Bacteriol. 180 (1998) 667-673. [PMID: 9457873]
3. Koski, M.K., Haapalainen, A.M., Hiltunen, J.K. and Glumoff, T. Crystallization and preliminary crystallographic data of 2-enoyl-CoA hydratase 2 domain of Candida tropicalis peroxisomal multifunctional enzyme type 2. Acta Crystallogr. D Biol. Crystallogr. 59 (2003) 1302-1305. [PMID: 12832794]
4. Hisano, T., Fukui, T., Iwata, T. and Doi, Y. Crystallization and preliminary X-ray analysis of (R)-specific enoyl-CoA hydratase from Aeromonas caviae involved in polyhydroxyalkanoate biosynthesis. Acta Crystallogr. D Biol. Crystallogr. 57 (2001) 145-147. [PMID: 11134939]
5. Goepfert, S., Hiltunen, J.K. and Poirier, Y. Identification and functional characterization of a monofunctional peroxisomal enoyl-CoA hydratase 2 that participates in the degradation of even cis-unsaturated fatty acids in Arabidopsis thaliana. J. Biol. Chem. 281 (2006) 35894-35903. [PMID: 16982622]
6. Engeland, K. and Kindl, H. Evidence for a peroxisomal fatty acid β-oxidation involving D-3-hydroxyacyl-CoAs. Characterization of two forms of hydro-lyase that convert D-(–)-3-hydroxyacyl-CoA into 2-trans-enoyl-CoA. Eur. J. Biochem. 200 (1991) 171-178. [PMID: 1879422]
Accepted name: 4-hydroxybutanoyl-CoA dehydratase
Reaction: 4-hydroxybutanoyl-CoA = but-3-enoyl-CoA + H2O
Glossary: 4-hydroxybutanoyl-CoA = 4-hydroxybutyryl-CoA
but-3-enoyl-CoA = vinylacetyl-CoA
Systematic name: 4-hydroxybutanoyl-CoA hydro-lyase
Comments: Contains FAD and a [3Fe-4S] iron-sulfur cluster. The enzyme is often present as a bifunctional enzyme, catalysing the dehydration of 4-hydroxybutanoyl-CoA to but-3-enoyl-CoA followed by isomerization of the later to crotonyl-CoA (EC 5.3.3.3). The enzyme has been characterized from several microorganisms, including Clostridium kluyveri, where it participates in succinate fermentation [1,2], Clostridium aminobutyricum, where it participates in 4-aminobutyrate degradation [3,4], and Metallosphaera sedula, where it participates in the 3-hydroxypropionate/4-hydroxybutyrate cycle, an autotrophic CO2 fixation pathway found in some thermoacidophilic archaea [5].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Bartsch, R.G. and Barker, H.A. A vinylacetyl isomerase from Clostridium kluyveri. Arch. Biochem. Biophys. 92 (1961) 122-132. [PMID: 13687513]
2. Scherf, U., Sohling, B., Gottschalk, G., Linder, D. and Buckel, W. Succinate-ethanol fermentation in Clostridium kluyveri: purification and characterisation of 4-hydroxybutyryl-CoA dehydratase/vinylacetyl-CoA Δ3-Δ2-isomerase. Arch. Microbiol. 161 (1994) 239-245. [PMID: 8161284]
3. Scherf, U. and Buckel, W. Purification and properties of an iron-sulfur and FAD-containing 4-hydroxybutyryl-CoA dehydratase/vinylacetyl-CoA Δ3-Δ2-isomerase from Clostridium aminobutyricum. Eur. J. Biochem. 215 (1993) 421-429. [PMID: 8344309]
4. Muh, U., Cinkaya, I., Albracht, S.P. and Buckel, W. 4-Hydroxybutyryl-CoA dehydratase from Clostridium aminobutyricum: characterization of FAD and iron-sulfur clusters involved in an overall non-redox reaction. Biochemistry 35 (1996) 11710-11718. [PMID: 8794752]
5. Berg, I.A., Kockelkorn, D., Buckel, W. and Fuchs, G. A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea. Science 318 (2007) 1782-1786. [PMID: 18079405]
Accepted name: colneleate synthase
Reaction: (9S,10E,12Z)-9-hydroperoxyoctadeca-10,12-dienoate = (8E)-9-[(1E,3Z)-nona-1,3-dien-1-yloxy]non-8-enoate + H2O
Glossary: colneleate = (8E)-9-[(1E,3Z)-nona-1,3-dien-1-yloxy]non-8-enoate
Other name(s): 9-divinyl ether synthase; 9-DES; CYP74D; CYP74D1; CYP74 cytochrome P-450; DES1
Systematic name: (8E)-9-[(1E,3E)-nona-1,3-dien-1-yloxy]non-8-enoate synthase
Comments: A heme-thiolate protein (P450) [2]. It catalyses the selective removal of pro-R hydrogen at C-8 in the biosynthesis of colneleic acid [4]. It forms also (8E)-9-[(1E,3Z,6Z)-nona-1,3,6-trien-1-yloxy]non-8-enoic acid (i.e. colnelenate) from (9S,10E,12Z,15Z)-9-hydroperoxy-10,12,15-octadecatrienoate. The corresponding 13-hydroperoxides are poor substrates [1,3]. The divinyl ethers colneleate and colnelenate have antimicrobial activity.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Stumpe, M., Kandzia, R., Gobel, C., Rosahl, S. and Feussner, I. A pathogen-inducible divinyl ether synthase (CYP74D) from elicitor-treated potato suspension cells. FEBS Lett. 507 (2001) 371-376. [PMID: 11696374]
2. Itoh, A. and Howe, G.A. Molecular cloning of a divinyl ether synthase. Identification as a CYP74 cytochrome P-450. J. Biol. Chem. 276 (2001) 3620-3627. [PMID: 11060314]
3. Fammartino, A., Cardinale, F., Gobel, C., Mene-Saffrane, L., Fournier, J., Feussner, I. and Esquerre-Tugaye, M.T. Characterization of a divinyl ether biosynthetic pathway specifically associated with pathogenesis in tobacco. Plant Physiol. 143 (2007) 378-388. [PMID: 17085514]
4. Hamberg, M. Hidden stereospecificity in the biosynthesis of divinyl ether fatty acids. FEBS J. 272 (2005) 736-743. [PMID: 15670154]
Accepted name: tryptophan synthase (indole-salvaging)
Reaction: L-serine + indole = L-tryptophan + H2O
Other name(s): tryptophan synthase β2
Systematic name: L-serine hydro-lyase [adding indole, L-tryptophan-forming]
Comments: Most mesophilic bacteria have a multimeric tryptophan synthase complex (EC 4.2.1.20) that forms L-tryptophan from L-serine and 1-C-(indol-3-yl)glycerol 3-phosphate via an indole intermediate. This intermediate, which is formed by the α subunits, is transferred in an internal tunnel to the β units, which convert it to tryptophan. In thermophilic organisms the high temperature enhances diffusion and causes the loss of indole. This enzyme, which does not combine with the α unit to form a complex, salvages the lost indole back to L-tryptophan. It has a much lower Km for indole than the β subunit of EC 4.2.1.20.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Hettwer, S. and Sterner, R. A novel tryptophan synthase β-subunit from the hyperthermophile Thermotoga maritima. Quaternary structure, steady-state kinetics, and putative physiological role. J. Biol. Chem. 277 (2002) 8194-8201. [PMID: 11756459]
Accepted name: tetrahymanol synthase
Reaction: tetrahymanol = squalene + H2O
For diagram of reaction click here.
Glossary: tetrahymanol = gammaceran-3β-ol
Other name(s): squalene–tetrahymanol cyclase
Systematic name: squalene hydro-lyase (tetrahymanol forming)
Comments: The reaction occurs in the reverse direction.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Saar, J., Kader, J.C., Poralla, K. and Ourisson, G. Purification and some properties of the squalene-tetrahymanol cyclase from Tetrahymena thermophila. Biochim. Biophys. Acta 1075 (1991) 93-101. [PMID: 1892870]
2. Giner, J.L., Rocchetti, S., Neunlist, S., Rohmer, M. and Arigoni, D. Detection of 1,2-hydride shifts in the formation of euph-7-ene by the squalene-tetrahymanol cyclase of Tetrahymena pyriformis. Chem. Commun. (Camb.) (2005) 3089-3091. [PMID: 15959594]
Accepted name: arabidiol synthase
Reaction: arabidiol = (3S)-2,3-epoxy-2,3-dihydrosqualene + H2O
For diagram of reaction click here.
Glossary: arabidiol = (13R)-malabarica-17,21-diene-3β,14-diol
Other name(s): PEN1 (gene name); (S)-squalene-2,3-epoxide hydro-lyase (arabidiol forming)
Systematic name: (3S)-2,3-epoxy-2,3-dihydrosqualene hydro-lyase (arabidiol forming)
Comments: The reaction occurs in the reverse direction.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Xiang, T., Shibuya, M., Katsube, Y., Tsutsumi, T., Otsuka, M., Zhang, H., Masuda, K. and Ebizuka, Y. A new triterpene synthase from Arabidopsis thaliana produces a tricyclic triterpene with two hydroxyl groups. Org Lett 8 (2006) 2835-2838. [PMID: 16774269]
Accepted name: dammarenediol II synthase
Reaction: dammarenediol II = (3S)-2,3-epoxy-2,3-dihydrosqualene + H2O
For diagram of reaction click here.
Other name(s): dammarenediol synthase; 2,3-oxidosqualene (20S)-dammarenediol cyclase; DDS; (S)-squalene-2,3-epoxide hydro-lyase (dammarenediol-II forming)
Systematic name: (3S)-2,3-epoxy-2,3-dihydrosqualene hydro-lyase (dammarenediol-II forming)
Comments: The reaction occurs in the reverse direction.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Tansakul, P., Shibuya, M., Kushiro, T. and Ebizuka, Y. Dammarenediol-II synthase, the first dedicated enzyme for ginsenoside biosynthesis, in Panax ginseng. FEBS Lett. 580 (2006) 5143-5149. [PMID: 16962103]
2. Han, J.Y., Kwon, Y.S., Yang, D.C., Jung, Y.R. and Choi, Y.E. Expression and RNA interference-induced silencing of the dammarenediol synthase gene in Panax ginseng. Plant Cell Physiol. 47 (2006) 1653-1662. [PMID: 17088293]
Accepted name: N-acetylmuramic acid 6-phosphate etherase
Reaction: N-acetylmuramate 6-phosphate + H2O = (R)-lactate + N-acetyl-D-glucosamine 6-phosphate
Other name(s): MurNAc-6-P etherase; MurQ
Systematic name: N-acetylmuramic acid 6-phosphate hydro-lyase (N-acetyl-D-glucosamine 6-phosphate forming)
Comments: This enzyme, along with EC 2.7.1.170, anhydro-N-acetylmuramic acid kinase, is required for the utilization of anhydro-N-acetylmuramic acid in proteobacteria. The substrate is either imported from the medium or derived from the bacterium's own cell wall murein during cell wall recycling.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Jaeger, T., Arsic, M. and Mayer, C. Scission of the lactyl ether bond of N-acetylmuramic acid by Escherichia coli "etherase". J. Biol. Chem. 280 (2005) 30100-30106. [PMID: 15983044]
2. Uehara, T., Suefuji, K., Valbuena, N., Meehan, B., Donegan, M. and Park, J.T. Recycling of the anhydro-N-acetylmuramic acid derived from cell wall murein involves a two-step conversion to N-acetylglucosamine-phosphate. J. Bacteriol. 187 (2005) 3643-3649. [PMID: 15901686]
3. Uehara, T., Suefuji, K., Jaeger, T., Mayer, C. and Park, J.T. MurQ etherase is required by Escherichia coli in order to metabolize anhydro-N-acetylmuramic acid obtained either from the environment or from its own cell wall. J. Bacteriol. 188 (2006) 1660-1662. [PMID: 16452451]
4. Hadi, T., Dahl, U., Mayer, C. and Tanner, M.E. Mechanistic studies on N-acetylmuramic acid 6-phosphate hydrolase (MurQ): an etherase involved in peptidoglycan recycling. Biochemistry 47 (2008) 11547-11558. [PMID: 18837509]
5. Jaeger, T. and Mayer, C. N-acetylmuramic acid 6-phosphate lyases (MurNAc etherases): role in cell wall metabolism, distribution, structure, and mechanism. Cell. Mol. Life Sci. 65 (2008) 928-939. [PMID: 18049859]
Accepted name: linalool dehydratase
Reaction: linalool = myrcene + H2O
For diagram click here.
Glossary: linalool = 3,7-dimethylocta-1,6-dien-3-ol
Other name(s): linalool hydro-lyase (myrcene-forming)
Systematic name: (3S)-linalool hydro-lyase (myrcene-forming)
Comments: In absence of oxygen the bifunctional linalool dehydratase-isomerase can catalyse in vitro two reactions, the hydration of myrcene to (3S)-linalool and the isomerization of (3S)-linalool to geraniol, the latter activity being classified as EC 5.4.4.4, geraniol isomerase.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Brodkorb, D., Gottschall, M., Marmulla, R., Lüddeke, F. and Harder, J. Linalool dehydratase-isomerase, a bifunctional enzyme in the anaerobic degradation of monoterpenes. J. Biol. Chem. 285 (2010) 30436-30442. [PMID: 20663876]
2. Lüddeke, F. and Harder, J. Enantiospecific (S)-(+)-linalool formation from β-myrcene by linalool dehydratase-isomerase. Z. Naturforsch. C 66 (2011) 409–412. [PMID: 21950166]
Accepted name: lupan-3β,20-diol synthase
Reaction: lupan-3β,20-diol = (3S)-2,3-epoxy-2,3-dihydrosqualene + H2O
For diagram of reaction click here.
Other name(s): LUP1 (gene name); (S)-squalene-2,3-epoxide hydro-lyase (lupan-3β,20-diol forming)
Systematic name: (3S)-2,3-epoxy-2,3-dihydrosqualene hydro-lyase (lupan-3β,20-diol forming)
Comments: The reaction occurs in the reverse direction. The recombinant enzyme from Arabidopsis thaliana gives a 1:1 mixture of lupeol and lupan-3β,20-diol with small amounts of β-amyrin, germanicol, taraxasterol and ψ-taraxasterol. See EC 5.4.99.41 (lupeol synthase).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Segura, M.J., Meyer, M.M. and Matsuda, S.P. Arabidopsis thaliana LUP1 converts oxidosqualene to multiple triterpene alcohols and a triterpene diol. Org. Lett. 2 (2000) 2257-2259. [PMID: 10930257]
2. Kushiro, T., Hoshino, M., Tsutsumi, T., Kawai, K., Shiro, M., Shibuya, M. and Ebizuka, Y. Stereochemical course in water addition during LUP1-catalyzed triterpene cyclization. Org. Lett. 8 (2006) 5589-5592. [PMID: 17107079]
Accepted name: squalene—hopanol cyclase
Reaction: hopan-22-ol = squalene + H2O
For diagram of reaction click here.
Other name(s): squalene—hopene cyclase (ambiguos)
Systematic name: hopan-22-ol hydro-lyase
Comments: The enzyme produces the cyclization products hopene (cf. EC 5.4.99.17) and hopanol from squalene at a constant ratio of 5:1.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Hoshino, T., Nakano, S., Kondo, T., Sato, T. and Miyoshi, A. Squalene-hopene cyclase: final deprotonation reaction, conformational analysis for the cyclization of (3R,S)-2,3-oxidosqualene and further evidence for the requirement of an isopropylidene moiety both for initiation of the polycyclization cascade and for the formation of the 5-membered E-ring. Org Biomol Chem 2 (2004) 1456-1470. [PMID: 15136801]
2. Sato, T., Kouda, M. and Hoshino, T. Site-directed mutagenesis experiments on the putative deprotonation site of squalene-hopene cyclase from Alicyclobacillus acidocaldarius. Biosci. Biotechnol. Biochem. 68 (2004) 728-738. [PMID: 15056909]
Accepted name: D-lactate dehydratase
Reaction: (R)-lactate = methylglyoxal + H2O
Other name(s): glyoxylase III
Systematic name: (R)-lactate hydro-lyase
Comments: The enzyme converts methylglyoxal to D-lactate in a single glutathione (GSH)-independent step. The other known route for this conversion is the two-step GSH-dependent pathway catalysed by EC 4.4.1.5 (lactoylglutathione lyase) and EC 3.1.2.6 (hydroxyacylglutathione hydrolase).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Misra, K., Banerjee, A.B., Ray, S. and Ray, M. Glyoxalase III from Escherichia coli: a single novel enzyme for the conversion of methylglyoxal into D-lactate without reduced glutathione. Biochem. J. 305 ( Pt 3) (1995) 999-1003. [PMID: 7848303]
2. Subedi, K.P., Choi, D., Kim, I., Min, B. and Park, C. Hsp31 of Escherichia coli K-12 is glyoxalase III. Mol. Microbiol. 81 (2011) 926-936. [PMID: 21696459]
Accepted name: carotenoid 1,2-hydratase
Reaction: (1) 1-hydroxy-1,2-dihydrolycopene = lycopene + H2O
(2) 1,1'-dihydroxy-1,1',2,2'-tetrahydrolycopene = 1-hydroxy-1,2-dihydrolycopene + H2O
For diagram of reaction click here or click here
Other name(s): CrtC
Systematic name: lycopene hydro-lyase (1-hydroxy-1,2-dihydrolycopene-forming)
Comments: In Rubrivivax gelatinosus [1] and Thiocapsa roseopersicina [2] both products are formed, whereas Rhodobacter capsulatus [1] only gives 1-hydroxy-1,2-dihydrolycopene. Also acts on neurosporene giving 1-hydroxy-1,2-dihydroneurosporene with both organism but 1,1'-dihydroxy-1,1',2,2'-tetrahydroneurosporene only with Rubrivivax gelatinosus.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Steiger, S., Mazet, A. and Sandmann, G. Heterologous expression, purification, and enzymatic characterization of the acyclic carotenoid 1,2-hydratase from Rubrivivax gelatinosus. Arch. Biochem. Biophys. 414 (2003) 51-58. [PMID: 12745254]
2. Hiseni, A., Arends, I.W. and Otten, L.G. Biochemical characterization of the carotenoid 1,2-hydratases (CrtC) from Rubrivivax gelatinosus and Thiocapsa roseopersicina. Appl. Microbiol. Biotechnol. (2011) . [PMID: 21590288]