Carnitine palmitoyltransferase in human erythrocyte membrane. Properties and malonyl-CoA sensitivity.
Carnitine palmitoyltransferase located in the erythrocyte plasma membrane is sensitive to inhibition by malonyl-CoA and 2-bromopalmitoyl-CoA plus carnitine. Although this inhibition and other properties suggest similarities to the intracellular enzymes in other tissues, no cross-reaction was observed with antisera to the peroxisomal or to the mitochondrial inner-membrane enzyme. The activity was solubilized by and was stable in Triton X-100, which destroys the enzymes found in microsomes and in the mitochondrial outer membrane. The substrate specificity is broader than for the intracellular enzymes, the activities with stearoyl-CoA (114%) and arachidonoyl-CoA (97%) being equal to that with palmitoyl-CoA, and the activities with linoleoyl-CoA (44%) and erucoyl-CoA (46%) about half that with palmitoyl-CoA. The function of this carnitine palmitoyltransferase is probably to buffer the acyl-CoA present in the erythrocyte for turnover of the fatty acyl groups of the membrane lipids.
Ramsay
R R
RR
Department of Biochemistry and Biophysics, University of California, San Francisco.
Mancinelli
G
G
Arduini
A
A
D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000037:antagonists & inhibitors / Q000097:blood*; D002417:Cattle; D004795:Enzyme Stability; D004910:Erythrocyte Membrane / Q000201:enzymology*; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology; D008316:Malonyl Coenzyme A / Q000494:pharmacology*; D008830:Microbodies / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D017830:Octoxynol; D011092:Polyethylene Glycols; D012995:Solubility; D013379:Substrate Specificity
D011092:Polyethylene Glycols; D008316:Malonyl Coenzyme A; D017830:Octoxynol; D002334:Carnitine O-Palmitoyltransferase