Enzymes
| UniProtKB help_outline | 3,206 proteins |
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- Name help_outline (R)-carnitine Identifier CHEBI:16347 (Beilstein: 4292315,5732837; CAS: 541-15-1) help_outline Charge 0 Formula C7H15NO3 InChIKeyhelp_outline PHIQHXFUZVPYII-ZCFIWIBFSA-N SMILEShelp_outline C[N+](C)(C)C[C@H](O)CC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 47 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 4,8-dimethylnonanoyl-CoA Identifier CHEBI:77061 Charge -4 Formula C32H52N7O17P3S InChIKeyhelp_outline YGNKJFPEXQCWDB-ANHZDMDASA-J SMILEShelp_outline CC(C)CCCC(C)CCC(=O)SCCNC(=O)CCNC(=O)[C@H](O)C(C)(C)COP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1OP([O-])([O-])=O)n1cnc2c(N)ncnc12 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CoA Identifier CHEBI:57287 (Beilstein: 11604429) help_outline Charge -4 Formula C21H32N7O16P3S InChIKeyhelp_outline RGJOEKWQDUBAIZ-IBOSZNHHSA-J SMILEShelp_outline CC(C)(COP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1OP([O-])([O-])=O)n1cnc2c(N)ncnc12)[C@@H](O)C(=O)NCCC(=O)NCCS 2D coordinates Mol file for the small molecule Search links Involved in 1,468 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline O-4,8-dimethylnonanoyl-(R)-carnitine Identifier CHEBI:84654 Charge 0 Formula C18H35NO4 InChIKeyhelp_outline DDTDJDZHDFMZED-OEMAIJDKSA-N SMILEShelp_outline CC(C)CCCC(C)CCC(=O)O[C@H](CC([O-])=O)C[N+](C)(C)C 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:44860 | RHEA:44861 | RHEA:44862 | RHEA:44863 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Publications
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Substrate specificity of human carnitine acetyltransferase: Implications for fatty acid and branched-chain amino acid metabolism.
Violante S., Ijlst L., Ruiter J., Koster J., van Lenthe H., Duran M., de Almeida I.T., Wanders R.J., Houten S.M., Ventura F.V.
Carnitine acyltransferases catalyze the reversible conversion of acyl-CoAs into acylcarnitine esters. This family includes the mitochondrial enzymes carnitine palmitoyltransferase 2 (CPT2) and carnitine acetyltransferase (CrAT). CPT2 is part of the carnitine shuttle that is necessary to import fat ... >> More
Carnitine acyltransferases catalyze the reversible conversion of acyl-CoAs into acylcarnitine esters. This family includes the mitochondrial enzymes carnitine palmitoyltransferase 2 (CPT2) and carnitine acetyltransferase (CrAT). CPT2 is part of the carnitine shuttle that is necessary to import fatty acids into mitochondria and catalyzes the conversion of acylcarnitines into acyl-CoAs. In addition, when mitochondrial fatty acid β-oxidation is impaired, CPT2 is able to catalyze the reverse reaction and converts accumulating long- and medium-chain acyl-CoAs into acylcarnitines for export from the matrix to the cytosol. However, CPT2 is inactive with short-chain acyl-CoAs and intermediates of the branched-chain amino acid oxidation pathway (BCAAO). In order to explore the origin of short-chain and branched-chain acylcarnitines that may accumulate in various organic acidemias, we performed substrate specificity studies using purified recombinant human CrAT. Various saturated, unsaturated and branched-chain acyl-CoA esters were tested and the synthesized acylcarnitines were quantified by ESI-MS/MS. We show that CrAT converts short- and medium-chain acyl-CoAs (C2 to C10-CoA), whereas no activity was observed with long-chain species. Trans-2-enoyl-CoA intermediates were found to be poor substrates for this enzyme. Furthermore, CrAT turned out to be active towards some but not all the BCAAO intermediates tested and no activity was found with dicarboxylic acyl-CoA esters. This suggests the existence of another enzyme able to handle the acyl-CoAs that are not substrates for CrAT and CPT2, but for which the corresponding acylcarnitines are well recognized as diagnostic markers in inborn errors of metabolism. << Less
Biochim. Biophys. Acta 1832:773-779(2013) [PubMed] [EuropePMC]
This publication is cited by 12 other entries.
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Carnitine palmitoyltransferase 2: New insights on the substrate specificity and implications for acylcarnitine profiling.
Violante S., Ijlst L., van Lenthe H., de Almeida I.T., Wanders R.J., Ventura F.V.
Over the last years acylcarnitines have emerged as important biomarkers for the diagnosis of mitochondrial fatty acid beta-oxidation (mFAO) and branched-chain amino acid oxidation disorders assuming they reflect the potentially toxic acyl-CoA species, accumulating intramitochondrially upstream of ... >> More
Over the last years acylcarnitines have emerged as important biomarkers for the diagnosis of mitochondrial fatty acid beta-oxidation (mFAO) and branched-chain amino acid oxidation disorders assuming they reflect the potentially toxic acyl-CoA species, accumulating intramitochondrially upstream of the enzyme block. However, the origin of these intermediates still remains poorly understood. A possibility exists that carnitine palmitoyltransferase 2 (CPT2), member of the carnitine shuttle, is involved in the intramitochondrial synthesis of acylcarnitines from accumulated acyl-CoA metabolites. To address this issue, the substrate specificity profile of CPT2 was herein investigated. Saccharomyces cerevisiae homogenates expressing human CPT2 were incubated with saturated and unsaturated C2-C26 acyl-CoAs and branched-chain amino acid oxidation intermediates. The produced acylcarnitines were quantified by ESI-MS/MS. We show that CPT2 is active with medium (C8-C12) and long-chain (C14-C18) acyl-CoA esters, whereas virtually no activity was found with short- and very long-chain acyl-CoAs or with branched-chain amino acid oxidation intermediates. Trans-2-enoyl-CoA intermediates were also found to be poor substrates for CPT2. Inhibition studies performed revealed that trans-2-C16:1-CoA may act as a competitive inhibitor of CPT2 (K(i) of 18.8 microM). The results obtained clearly demonstrate that CPT2 is able to reverse its physiological mechanism for medium and long-chain acyl-CoAs contributing to the abnormal acylcarnitines profiles characteristic of most mFAO disorders. The finding that trans-2-enoyl-CoAs are poorly handled by CPT2 may explain the absence of trans-2-enoyl-carnitines in the profiles of mitochondrial trifunctional protein deficient patients, the only defect where they accumulate, and the discrepancy between the clinical features of this and other long-chain mFAO disorders such as very long-chain acyl-CoA dehydrogenase deficiency. << Less
Biochim. Biophys. Acta 1802:728-732(2010) [PubMed] [EuropePMC]
This publication is cited by 10 other entries.
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Molecular cloning and expression of human carnitine octanoyltransferase: evidence for its role in the peroxisomal beta-oxidation of branched-chain fatty acids.
Ferdinandusse S., Mulders J., Ijlst L., Denis S., Dacremont G., Waterham H.R., Wanders R.J.A.
To study the putative role of human carnitine octanoyltransferase (COT) in the beta-oxidation of branched-chain fatty acids, we identified and cloned the cDNA encoding human COT and expressed it in the yeast Saccharomyces cerevisiae. Enzyme activity measurements showed that COT efficiently convert ... >> More
To study the putative role of human carnitine octanoyltransferase (COT) in the beta-oxidation of branched-chain fatty acids, we identified and cloned the cDNA encoding human COT and expressed it in the yeast Saccharomyces cerevisiae. Enzyme activity measurements showed that COT efficiently converts one of the end products of the peroxisomal beta-oxidation of pristanic acid, 4, 8-dimethylnonanoyl-CoA, to its corresponding carnitine ester. Production of the carnitine ester of this branched/medium-chain acyl-CoA within the peroxisome is required for its transport to the mitochondrion where further beta-oxidation occurs. In contrast, 4, 8-dimethylnonanoyl-CoA is not a substrate for carnitine acetyltransferase, another acyltransferase localized in peroxisomes, which catalyzes the formation of carnitine esters of the other products of pristanic acid beta-oxidation, namely acetyl-CoA and propionyl-CoA. Our results shed new light on the function of COT in fatty acid metabolism and point to a crucial role of COT in the beta-oxidation of branched-chain fatty acids. << Less
Biochem. Biophys. Res. Commun. 263:213-218(1999) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.