Enoyl coenzyme A reduction by bovine mammary fatty acid synthetase. Specificity and other characteristics.
The NADPH-dependent enoyl coenzyme A reductase activity of bovine mammary fatty acid synthetase has been characterized with regard to substrate specificity and the product formed. A relatively high specificity for an unsubstituted, four-carbon, 2,3-enoyl chain in trans configuration is obtained. Reduction of trans-crotonyl-CoA results in butyrate, 50% of which is coenzyme A-bound. The reaction is subject to product inhibition, specifically by butyryl-CoA and NADP. Free coenzyme A, on the other hand, is an activator. The pH profile, susceptibility to inhibition by -SH reagents, the results of the relative activities obtained with substrate analogues and homologues, and the ready use of crotonyl-CoA as a primer in fatty acid synthesis are consistent with a mechanism in which the crotonyl group is transferred to an -SH group, is reduced, and then is either transferred back to CoA or hydrolyzed.
D000214:Acyl Coenzyme A; D000818:Animals; D002417:Cattle; D044943:Fatty Acid Desaturases / Q000302:isolation & purification / Q000378:metabolism*; D064429:Fatty Acid Synthases / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008321:Mammary Glands, Animal / Q000201:enzymology*; D013379:Substrate Specificity
D000214:Acyl Coenzyme A; D044943:Fatty Acid Desaturases; D064429:Fatty Acid Synthases