title: Carnitine palmitoyltransferase. Activation by palmitoyl-CoA and inactivation by malonyl-CoA.
abstract: Extraction of rat liver mitochondria twice with 0.5% Triton X-100 in a salt-free medium leaves less than 10% of the carnitine palmitoyltransferase membrane bound. The remaining membrane-bound enzyme is inhibited virtually completely by 10 microM malonyl-CoA. Preincubation of the extracted membranes with palmitoyl-CoA and salts (KCI) for several minutes activates the enzyme and makes it increasingly insensitive to malonyl-CoA. Addition of malonyl-CoA to the preincubation reverses this desensitization. In albumin-containing media salts also decrease the binding of palmitoyl-CoA to albumin and stimulate carnitine palmitoyltransferase by increasing substrate availability in free solution. The reverse reaction shows accelerated desensitization by palmitoylcarnitine and resensitization by malonyl-CoA.
mesh_terms: D000214:Acyl Coenzyme A / Q000494:pharmacology*; D000217:Acyltransferases / Q000096:biosynthesis*; D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000096:biosynthesis* / Q000302:isolation & purification; D055598:Chemical Phenomena; D002621:Chemistry; D004789:Enzyme Activation / Q000187:drug effects*; D008316:Malonyl Coenzyme A / Q000494:pharmacology*; D008930:Mitochondria, Liver / Q000201:enzymology*; D010171:Palmitoyl Coenzyme A / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D013379:Substrate Specificity
chemical_list: D000214:Acyl Coenzyme A; D010171:Palmitoyl Coenzyme A; D008316:Malonyl Coenzyme A; D011189:Potassium Chloride; D000217:Acyltransferases; D002334:Carnitine O-Palmitoyltransferase