Substrate inhibition of carnitine palmitoyltransferase by palmitoyl-CoA and activation by phospholipids and proteins.
When carnitine palmitoyltransferase is purified it shows increasing substrate inhibition by palmitoyl-CoA as the protein content of the assay mixture is decreased. The purified enzyme is stimulated by addition of phospholipids (phosphatidylcholine, cardiolipin) and proteins (albumin, fatty acid-binding protein, lambda-globulin) to the reaction mixture. The effects of phospholipid and protein are more than additive, particularly with relatively high concentrations of palmitoyl-CoA. It is suggested that the enzyme contains hydrophobic sites which require phospholipid to prevent spurious binding of palmitoyl-CoA and which normally anchor the enzyme to the mitochondrial membrane.
D000214:Acyl Coenzyme A / Q000494:pharmacology*; D000217:Acyltransferases / Q000037:antagonists & inhibitors*; D000418:Albumins / Q000494:pharmacology; D002334:Carnitine O-Palmitoyltransferase / Q000037:antagonists & inhibitors*; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D010171:Palmitoyl Coenzyme A / Q000494:pharmacology*; D010743:Phospholipids / Q000494:pharmacology*; D011506:Proteins / Q000494:pharmacology*
D000214:Acyl Coenzyme A; D000418:Albumins; D010743:Phospholipids; D011506:Proteins; D010171:Palmitoyl Coenzyme A; D000217:Acyltransferases; D002334:Carnitine O-Palmitoyltransferase