EC |
1.3.8.13 |
Accepted name: |
crotonobetainyl-CoA reductase |
Reaction: |
γ-butyrobetainyl-CoA + electron-transfer flavoprotein = crotonobetainyl-CoA + reduced electron-transfer flavoprotein |
Glossary: |
γ-butyrobetainyl-CoA = 4-(trimethylammonio)butanoyl-CoA
crotonobetainyl-CoA = (E)-4-(trimethylammonio)but-2-enoyl-CoA |
Other name(s): |
caiA (gene name) |
Systematic name: |
γ-butyrobetainyl-CoA:electron-transfer flavoprotein 2,3-oxidoreductase |
Comments: |
The enzyme has been purified from the bacterium Escherichia coli O44 K74, in which it forms a complex with EC 2.8.3.21, L-carnitine CoA-transferase. The electron donor is believed to be an electron-transfer flavoprotein (ETF) encoded by the fixA and fixB genes. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Roth, S., Jung, K., Jung, H., Hommel, R.K. and Kleber, H.P. Crotonobetaine reductase from Escherichia coli - a new inducible enzyme of anaerobic metabolization of L(–)-carnitine. Antonie Van Leeuwenhoek 65 (1994) 63–69. [PMID: 8060125] |
2. |
Preusser, A., Wagner, U., Elssner, T. and Kleber, H.P. Crotonobetaine reductase from Escherichia coli consists of two proteins. Biochim. Biophys. Acta 1431 (1999) 166–178. [DOI] [PMID: 10209289] |
3. |
Elssner, T., Hennig, L., Frauendorf, H., Haferburg, D. and Kleber, H.P. Isolation, identification, and synthesis of γ-butyrobetainyl-CoA and crotonobetainyl-CoA, compounds involved in carnitine metabolism of E. coli. Biochemistry 39 (2000) 10761–10769. [DOI] [PMID: 10978161] |
4. |
Walt, A. and Kahn, M.L. The fixA and fixB genes are necessary for anaerobic carnitine reduction in Escherichia coli. J. Bacteriol. 184 (2002) 4044–4047. [DOI] [PMID: 12081978] |
|
[EC 1.3.8.13 created 2017] |
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|
|
|
EC |
1.14.13.239 |
Accepted name: |
carnitine monooxygenase |
Reaction: |
L-carnitine + NAD(P)H + H+ + O2 = (3R)-3-hydroxy-4-oxobutanoate + trimethylamine + NAD(P)+ + H2O |
Glossary: |
(3R)-3-hydroxy-4-oxobutanoate = L-malic semialdehyde |
Other name(s): |
cntAB (gene names); yeaWX (gene names) |
Systematic name: |
L-carnitine,NAD(P)H:oxygen oxidoreductase (trimethylamine-forming) |
Comments: |
The bacterial enzyme is a complex consisting of a reductase and an oxygenase components. The reductase subunit contains a flavin and a plant-type ferredoxin [2Fe-2S] cluster, while the oxygenase subunit is a Rieske-type protein in which a [2Fe-2S] cluster is coordinated by two histidine and two cysteine residues. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
References: |
1. |
Ditullio, D., Anderson, D., Chen, C.S. and Sih, C.J. L-Carnitine via enzyme-catalyzed oxidative kinetic resolution. Bioorg. Med. Chem. 2 (1994) 415–420. [DOI] [PMID: 8000862] |
2. |
Zhu, Y., Jameson, E., Crosatti, M., Schafer, H., Rajakumar, K., Bugg, T.D. and Chen, Y. Carnitine metabolism to trimethylamine by an unusual Rieske-type oxygenase from human microbiota. Proc. Natl. Acad. Sci. USA 111 (2014) 4268–4273. [DOI] [PMID: 24591617] |
3. |
Koeth, R.A., Levison, B.S., Culley, M.K., Buffa, J.A., Wang, Z., Gregory, J.C., Org, E., Wu, Y., Li, L., Smith, J.D., Tang, W.H., DiDonato, J.A., Lusis, A.J. and Hazen, S.L. γ-Butyrobetaine is a proatherogenic intermediate in gut microbial metabolism of L-carnitine to TMAO. Cell Metab 20 (2014) 799–812. [DOI] [PMID: 25440057] |
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[EC 1.14.13.239 created 2017] |
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EC |
2.1.1.383 |
Accepted name: |
L-carnitine—corrinoid protein Co-methyltransferase |
Reaction: |
L-carnitine + a [Co(I) quaternary-amine-specific corrinoid protein] = a [methyl-Co(III) quaternary-amine-specific corrinoid protein] + L-norcarnitine |
Glossary: |
L-norcarnitine = (3R)-4-(dimethylamino)-3-hydroxybutanoate |
Other name(s): |
mtcB (gene name) |
Systematic name: |
L-carnitine:[Co(I) quaternary-amine-specific corrinoid protein] Co-methyltransferase |
Comments: |
The enzyme, characterized from the bacterium Eubacterium limosum, is a component of a system that transfers a methyl group from L-carnitine to tetrahydrofolate, as part of an L-carnitine degradation pathway. The resulting 5-methyltetrahydrofolate is processed to acetyl-CoA via the Wood—Ljungdahl pathway. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Kountz, D.J., Behrman, E.J., Zhang, L. and Krzycki, J.A. MtcB, a member of the MttB superfamily from the human gut acetogen Eubacterium limosum, is a cobalamin-dependent carnitine demethylase. J. Biol. Chem. 295 (2020) 11971–11981. [DOI] [PMID: 32571881] |
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[EC 2.1.1.383 created 2021] |
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EC |
2.1.1.389 |
Accepted name: |
[methyl-Co(III) quaternary-amine-specific corrinoid protein]—tetrahydrofolate methyltransferase |
Reaction: |
a [methyl-Co(III) quaternary-amine-specific corrinoid protein] + tetrahydrofolate = N5-methyltetrahydrofolate + a [Co(I) quaternary-amine-specific corrinoid protein] |
Other name(s): |
mtqA (gene name) (ambiguous); [methyl-Co(III) MtqC corrinoid protein]—tetrahydrofolate methyltransferase |
Systematic name: |
[methyl-Co(III) quaternary-amine-specific corrinoid protein]:tetrahydrofolate methyltransferase |
Comments: |
The enzyme, characterized from the acetogenic gut bacterium Eubacterium limosum, participates in a pathway for the degradation of some quaternary amine compounds (L-proline betaine and L-carnitine). The enzyme catalyses the transfer of a methyl group bound to the cobalt cofactor of a dedicated corrinoid protein (bacterial MtqC) to tetrahydrofolate. The resulting 5-methyltetrahydrofolate is processed to acetyl-CoA via the Wood—Ljungdahl pathway. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Picking, J.W., Behrman, E.J., Zhang, L. and Krzycki, J.A. MtpB, a member of the MttB superfamily from the human intestinal acetogen Eubacterium limosum, catalyzes proline betaine demethylation. J. Biol. Chem. 294 (2019) 13697–13707. [DOI] [PMID: 31341018] |
2. |
Kountz, D.J., Behrman, E.J., Zhang, L. and Krzycki, J.A. MtcB, a member of the MttB superfamily from the human gut acetogen Eubacterium limosum, is a cobalamin-dependent carnitine demethylase. J. Biol. Chem. 295 (2020) 11971–11981. [DOI] [PMID: 32571881] |
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[EC 2.1.1.389 created 2023] |
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EC |
2.3.1.21 |
Accepted name: |
carnitine O-palmitoyltransferase |
Reaction: |
palmitoyl-CoA + L-carnitine = CoA + L-palmitoylcarnitine |
Other name(s): |
CPT (ambiguous); CPTo; outer malonyl-CoA inhibitable carnitine palmitoyltransferase; CPTi; CPT I (outer membrane carnitine palmitoyl transferase); carnitine palmitoyltransferase I; carnitine palmitoyltransferase II; CPT-A; CPT-B; acylcarnitine transferase; carnitine palmitoyltransferase; carnitine palmitoyltransferase-A; L-carnitine palmitoyltransferase; palmitoylcarnitine transferase |
Systematic name: |
palmitoyl-CoA:L-carnitine O-palmitoyltransferase |
Comments: |
Broad specificity to acyl group, over the range C8 to C18; optimal activity with palmitoyl-CoA. cf. EC 2.3.1.7 carnitine O-acetyltransferase and EC 2.3.1.137 carnitine O-octanoyltransferase. |
Links to other databases: |
BRENDA, EXPASY, GTD, KEGG, MetaCyc, PDB, CAS registry number: 9068-41-1 |
References: |
1. |
Derrick, J.P., Tubbs, P.K. and Ramsay, R.R. Purification and properties of an easily solubilized L-carnitine palmitoyltransferase from beef-liver mitochondria. Biochem. Soc. Trans. 14 (1986) 698. |
2. |
Healy, M.J., Kerner, J. and Bieber, L.L. Enzymes of carnitine acylation. Is overt carnitine palmitoyltransferase of liver peroxisomal carnitine octanoyltransferase? Biochem. J. 249 (1988) 231–237. [PMID: 3342008] |
3. |
Miyazawa, S., Ozasa, H., Osumi, T. and Hashimoto, T. Purification and properties of carnitine octanoyltransferase and carnitine palmitoyltransferase from rat liver. J. Biochem. (Tokyo) 94 (1983) 529–542. [PMID: 6630173] |
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[EC 2.3.1.21 created 1972] |
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EC |
2.3.1.137 |
Accepted name: |
carnitine O-octanoyltransferase |
Reaction: |
octanoyl-CoA + L-carnitine = CoA + L-octanoylcarnitine |
Other name(s): |
medium-chain/long-chain carnitine acyltransferase; carnitine medium-chain acyltransferase; easily solubilized mitochondrial carnitine palmitoyltransferase; overt mitochondrial carnitine palmitoyltransferase |
Systematic name: |
octanoyl-CoA:L-carnitine O-octanoyltransferase |
Comments: |
Acts on a range of acyl-CoAs, with optimal activity with C6 or C8 acyl groups. cf. EC 2.3.1.7 (carnitine O-acetyltransferase) and EC 2.3.1.21 (carnitine O-palmitoyltransferase). |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 39369-19-2 |
References: |
1. |
Farrell, S.O., Fiol, C.J., Reddy, J.K. and Bieber, L.L. Properties of purified carnitine acyltransferases of mouse liver peroxisomes. J. Biol. Chem. 259 (1984) 13089–13095. [PMID: 6436243] |
2. |
Healy, M.J., Kerner, J. and Bieber, L.L. Enzymes of carnitine acylation. Is overt carnitine palmitoyltransferase of liver peroxisomal carnitine octanoyltransferase? Biochem. J. 249 (1988) 231–237. [PMID: 3342008] |
3. |
Miyazawa, S., Ozasa, H., Osumi, T. and Hashimoto, T. Purification and properties of carnitine octanoyltransferase and carnitine palmitoyltransferase from rat liver. J. Biochem. (Tokyo) 94 (1983) 529–542. [PMID: 6630173] |
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[EC 2.3.1.137 created 1992] |
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EC |
2.8.3.21 |
Accepted name: |
L-carnitine CoA-transferase |
Reaction: |
(1) (E)-4-(trimethylammonio)but-2-enoyl-CoA + L-carnitine = (E)-4-(trimethylammonio)but-2-enoate + L-carnitinyl-CoA (2) 4-trimethylammoniobutanoyl-CoA + L-carnitine = 4-trimethylammoniobutanoate + L-carnitinyl-CoA |
Glossary: |
L-carnitine = (3R)-3-hydroxy-4-(trimethylammonio)butanoate
(E)-4-(trimethylammonio)but-2-enoate = crotonobetaine
4-trimethylammoniobutanoate = γ-butyrobetaine |
Other name(s): |
CaiB; crotonobetainyl/γ-butyrobetainyl-CoA:carnitine CoA-transferase |
Systematic name: |
(E)-4-(trimethylammonio)but-2-enoyl-CoA:L-carnitine CoA-transferase |
Comments: |
The enzyme is found in gammaproteobacteria such as Proteus sp. and Escherichia coli. It has similar activity with both substrates. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
References: |
1. |
Engemann, C., Elssner, T. and Kleber, H.P. Biotransformation of crotonobetaine to L-(–)-carnitine in Proteus sp. Arch. Microbiol. 175 (2001) 353–359. [PMID: 11409545] |
2. |
Elssner, T., Engemann, C., Baumgart, K. and Kleber, H.P. Involvement of coenzyme A esters and two new enzymes, an enoyl-CoA hydratase and a CoA-transferase, in the hydration of crotonobetaine to L-carnitine by Escherichia coli. Biochemistry 40 (2001) 11140–11148. [DOI] [PMID: 11551212] |
3. |
Stenmark, P., Gurmu, D. and Nordlund, P. Crystal structure of CaiB, a type-III CoA transferase in carnitine metabolism. Biochemistry 43 (2004) 13996–14003. [DOI] [PMID: 15518548] |
4. |
Engemann, C., Elssner, T., Pfeifer, S., Krumbholz, C., Maier, T. and Kleber, H.P. Identification and functional characterisation of genes and corresponding enzymes involved in carnitine metabolism of Proteus sp. Arch. Microbiol. 183 (2005) 176–189. [DOI] [PMID: 15731894] |
5. |
Rangarajan, E.S., Li, Y., Iannuzzi, P., Cygler, M. and Matte, A. Crystal structure of Escherichia coli crotonobetainyl-CoA: carnitine CoA-transferase (CaiB) and its complexes with CoA and carnitinyl-CoA. Biochemistry 44 (2005) 5728–5738. [DOI] [PMID: 15823031] |
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[EC 2.8.3.21 created 2014] |
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EC |
3.1.1.28 |
Accepted name: |
acylcarnitine hydrolase |
Reaction: |
O-acylcarnitine + H2O = a fatty acid + L-carnitine |
Other name(s): |
high activity acylcarnitine hydrolase; HACH; carnitine ester hydrolase; palmitoylcarnitine hydrolase; palmitoyl-L-carnitine hydrolase; long-chain acyl-L-carnitine hydrolase; palmitoyl carnitine hydrolase |
Systematic name: |
O-acylcarnitine acylhydrolase |
Comments: |
Acts on higher fatty acid (C6 to C18) esters of L-carnitine; highest activity is with O-decanoyl-L-carnitine. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37278-42-5 |
References: |
1. |
Mahadevan, S. and Sauer, F. Carnitine ester hydrolase of rat liver. J. Biol. Chem. 244 (1969) 4448–4453. [PMID: 5806585] |
2. |
Mentlein, R., Reuter, G. and Heymann, E. Specificity of two different purified acylcarnitine hydrolases from rat liver, their identity with other carboxylesterases, and their possible function. Arch. Biochem. Biophys. 240 (1985) 801–810. [DOI] [PMID: 4026306] |
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[EC 3.1.1.28 created 1972] |
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EC |
3.1.2.33 |
Accepted name: |
betainyl-CoA thioesterase |
Reaction: |
betaine-CoA + H2O = glycine betaine + CoA |
Glossary: |
betaine-CoA = glycinebetainyl-CoA = betainyl-CoA = N,N,N-trimethylglycyl-CoA |
Other name(s): |
cdhB (gene name) |
Systematic name: |
betaine-CoA hydrolase |
Comments: |
The enzyme, characterized from the bacterium Pseudomonas aeruginosa, is involved in an L-carnitine degradation pathway. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Wargo, M.J. and Hogan, D.A. Identification of genes required for Pseudomonas aeruginosa carnitine catabolism. Microbiology (Reading) 155 (2009) 2411–2419. [DOI] [PMID: 19406895] |
2. |
Bastard, K., Smith, A.A., Vergne-Vaxelaire, C., Perret, A., Zaparucha, A., De Melo-Minardi, R., Mariage, A., Boutard, M., Debard, A., Lechaplais, C., Pelle, C., Pellouin, V., Perchat, N., Petit, J.L., Kreimeyer, A., Medigue, C., Weissenbach, J., Artiguenave, F., De Berardinis, V., Vallenet, D. and Salanoubat, M. Revealing the hidden functional diversity of an enzyme family. Nat. Chem. Biol. 10 (2014) 42–49. [DOI] [PMID: 24240508] |
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[EC 3.1.2.33 created 2024] |
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EC |
3.5.1.73 |
Accepted name: |
carnitinamidase |
Reaction: |
L-carnitinamide + H2O = L-carnitine + NH3 |
Other name(s): |
L-carnitinamidase; carnitine amidase; L-carnitine amidase |
Systematic name: |
L-carnitinamide amidohydrolase |
Comments: |
Does not act on D-carnitinamide. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 117444-04-9 |
References: |
1. |
Nakayama, K., Honda, H., Ogawa, Y., Ozawa, T. and Ota, T. Method for producing carnitine, L- carnitinamide hydrolase and method for producing same. Patent DE3728321, Chem. Abstr. (1988), 109, 22873. |
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[EC 3.5.1.73 created 1992] |
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EC
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4.2.1.89
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Deleted entry: | carnitine dehydratase. The activity has now been shown to be due to EC 2.8.3.21, L-carnitine CoA-transferase and EC 4.2.1.149, crotonobetainyl-CoA hydratase. |
[EC 4.2.1.89 created 1989, deleted 2014] |
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EC |
4.2.1.149 |
Accepted name: |
crotonobetainyl-CoA hydratase |
Reaction: |
L-carnitinyl-CoA = (E)-4-(trimethylammonio)but-2-enoyl-CoA + H2O |
Glossary: |
L-carnitinyl-CoA = (3R)-3-hydroxy-4-(trimethylammonio)butanoyl-CoA
(E)-4-(trimethylammonio)but-2-enoyl-CoA = crotonobetainyl-CoA |
Other name(s): |
CaiD; L-carnityl-CoA dehydratase |
Systematic name: |
L-carnitinyl-CoA hydro-lyase [(E)-4-(trimethylammonio)but-2-enoyl-CoA-forming] |
Comments: |
The enzyme is also able to use crotonyl-CoA as substrate, with low efficiency [2]. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Engemann, C., Elssner, T. and Kleber, H.P. Biotransformation of crotonobetaine to L-(–)-carnitine in Proteus sp. Arch. Microbiol. 175 (2001) 353–359. [PMID: 11409545] |
2. |
Elssner, T., Engemann, C., Baumgart, K. and Kleber, H.P. Involvement of coenzyme A esters and two new enzymes, an enoyl-CoA hydratase and a CoA-transferase, in the hydration of crotonobetaine to L-carnitine by Escherichia coli. Biochemistry 40 (2001) 11140–11148. [DOI] [PMID: 11551212] |
3. |
Engemann, C., Elssner, T., Pfeifer, S., Krumbholz, C., Maier, T. and Kleber, H.P. Identification and functional characterisation of genes and corresponding enzymes involved in carnitine metabolism of Proteus sp. Arch. Microbiol. 183 (2005) 176–189. [DOI] [PMID: 15731894] |
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[EC 4.2.1.149 created 2014] |
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EC |
6.2.1.48 |
Accepted name: |
carnitine—CoA ligase |
Reaction: |
ATP + L-carnitine + CoA = AMP + diphosphate + L-carnitinyl-CoA |
Glossary: |
carnitine = 3-hydroxy-4-(trimethylammonio)butanoate
crotonobetaine = (E)-4-(trimethylammonio)but-2-enoate
γ-butyrobetaine = 4-(trimethylammonio)butanoate |
Other name(s): |
caiC (gene name) |
Systematic name: |
L-carnitine:CoA ligase (AMP-forming) |
Comments: |
The enzyme, originally characterized from the bacterium Escherichia coli, can catalyse the transfer of CoA to L-carnitine, crotonobetaine and γ-butyrobetaine. In vitro the enzyme also exhibits the activity of EC 2.8.3.21, L-carnitine CoA-transferase. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc |
References: |
1. |
Eichler, K., Bourgis, F., Buchet, A., Kleber, H.P. and Mandrand-Berthelot, M.A. Molecular characterization of the cai operon necessary for carnitine metabolism in Escherichia coli. Mol. Microbiol. 13 (1994) 775–786. [DOI] [PMID: 7815937] |
2. |
Bernal, V., Arense, P., Blatz, V., Mandrand-Berthelot, M.A., Canovas, M. and Iborra, J.L. Role of betaine:CoA ligase (CaiC) in the activation of betaines and the transfer of coenzyme A in Escherichia coli. J. Appl. Microbiol. 105 (2008) 42–50. [DOI] [PMID: 18266698] |
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[EC 6.2.1.48 created 2017] |
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