Purification and properties of carnitine acetyltransferase from human liver

W. Bloisi, I. Colombo, B. Garavaglia, R. Giardini, G. Finocchiaro, S. Didonato

Research output: Contribution to journalArticlepeer-review

Abstract

Carnitine acetyltransferase was purified from the supernatant obtained after centrifugation of human liver homogenate to a final specific activity of 78.75 unit·mg-1 with acetyl-CoA as a substrate. Human carnitine acetyltransferase is a monomer of 60.5 kDa with maximum in the presence of propionyl-CoA and a pH optimum of 8.7. Apparent K(m) values for acetyl-CoA are three times lower than for decanoyl-CoA. K(m) values for L-carnitine in the presence of acetyl-CoA are six times lower than in the presence of decanoyl-CoA. K(m) values for acetylcarnitine are three times lower than for octanoylcarnitine. The polyclonal antibodies against human carnitine acetyltransferase recognize a 60.5-kDa peptide in the purified preparation of human liver and brain homogenates and in immunoblots of mitochonddrial and peroxisomal fractions from human liver. Immunoprecipitation and SDS/PAGE analysis of 35S-labelled proteins produced by human fibroblasts indicate that mitochondrial carnitine acetyltransferase is synthesized as a precusor of 65 kDa. We also purified carnitine acetyltransferase from the pellet obtained after centrifugation of liver homogenate. The pellet was extracted by sonication in the presence of 0.5% Tween 20. The chromatographic procedures for the purification and the kinetic, physical and immunological properties of pellet-extracted carnitine acetyltransferase are similar to those of carnitine acetyltransferase purified from the supernatant of human liver homogenate.

Original languageEnglish
Pages (from-to)539-546
Number of pages8
JournalEuropean Journal of Biochemistry
Volume189
Issue number3
DOIs
Publication statusPublished - 1990

ASJC Scopus subject areas

  • Biochemistry

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