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. 1967 Aug;104(2):510–518. doi: 10.1042/bj1040510

The substrate specificity of carnitine acetyltransferase

J F A Chase 1
PMCID: PMC1270613  PMID: 6069132

Abstract

1. A study of the acyl group specificity of the carnitine acetyltransferase reaction [acyl-(−)carnitine+CoASH ⇌ (−)-carnitine+acyl-CoA] has been made with the enzyme from pigeon breast muscle. Acyl groups containing up to 10 carbon atoms are transferred and detailed kinetic investigations with a range of acyl-CoA and acylcarnitine substrates are reported. 2. Acyl-CoA derivatives with 12 or more carbon atoms in the acyl group are potent reversible inhibitors of carnitine acetyltransferase, competing with acetyl-CoA. Lauroyl- and myristoyl-CoA show a mixed inhibition with respect to (−)-carnitine, but palmitoyl-CoA competes strictly with this substrate also. Palmitoyl-dl-carnitine shows none of these effects. 3. Ammonium palmitate inhibits the enzyme competitively with respect to (−)-carnitine and non-competitively with respect to acetyl-CoA. 4. It is suggested that a hydrophobic site exists on the carnitine acetyltransferase molecule. The hydrocarbon chain of an acyl-CoA derivative containing eight or more carbon atoms in the acyl group may interact with this, which results in enhanced acyl-CoA binding. Competition occurs between ligands bound to this hydrophobic site and the carnitine binding site. 5. The possible physiological significance of long-chain acyl-CoA inhibition of this enzyme is discussed.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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