Reaction of yeast fatty acid synthetase with iodoacetamide. 3. Malonyl-coenzyme A decarboxylase as product of the reaction of fatty acid synthetase with iodoacetamide.
Yeast fatty acid synthetase possesses very low malonyl-CoA decarboxylase activity. Treatment with iodoacetamide, while abolishing synthetase activity, induces a strong malonyl decarboxylase activity which, in turn, can be inhibited by N-ethylmaleimide. Kinetic analysis shows that the emergence of the decarboxylase activity is synchronized to the disappearance of the fatty-acid-synthesizing activity and thus, is due to carboxamidomethylation of the peripheral SH-groups of the multienzyme complex. Strong decarboxylase activity was also found after treatment of the synthetase with methylmalonyl-CoA. A hypothetical scheme is proposed which explains the origination of the decarboxylase activity as a consequence of conformational changes of the condensing enzyme component which happen when the peripheral SH-group is acylated or alkylated.
D001665:Binding Sites; D002262:Carboxy-Lyases / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology; D064429:Fatty Acid Synthases / Q000378:metabolism*; D007460:Iodoacetamide / Q000494:pharmacology*; D007461:Iodoacetates / Q000494:pharmacology*; D007700:Kinetics; D008316:Malonyl Coenzyme A; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D007461:Iodoacetates; D008316:Malonyl Coenzyme A; D064429:Fatty Acid Synthases; D002262:Carboxy-Lyases; C021532:malonyl-CoA decarboxylase; D005033:Ethylmaleimide; D007460:Iodoacetamide