Coenzyme A requirement for the termination reaction of rat liver fatty acid synthetase.
Highly purified rat liver fatty acid synthetase is completely inhibited when assayed in the presence of a coenzyme A-depleting system such as that catalyzed by phosphotransacetylase, acetyl-CoA synthetase, or ATP citrate lyase. The addition of free CoA causes a reversal of this inhibition. The requirement of free CoA is the same whether acetyl-CoA or butyryl-CoA serves as the primer for fatty acid synthetase. The CoA-depleted and thus inactive fatty acid synthetase system can be reactivated by the addition of a rat brain thioesterase or a rat mammary gland thioesterase II preparation. This reactivation appears to occur in the absence of free CoA. Long chain fatty acids (mainly palmitate) are formed by the thioesterase reactivated system. These results suggest that CoA is required for the termination of the fatty acid synthetase reaction. Possible mechanisms are discussed.
D001275:ATP Citrate (pro-S)-Lyase / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology; D003065:Coenzyme A / Q000494:pharmacology*; D004789:Enzyme Activation; D064429:Fatty Acid Synthases / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008321:Mammary Glands, Animal / Q000201:enzymology; D051381:Rats; D013869:Thiolester Hydrolases / Q000378:metabolism
D064429:Fatty Acid Synthases; D001275:ATP Citrate (pro-S)-Lyase; D013869:Thiolester Hydrolases; D003065:Coenzyme A