The development and application of a novel chromophoric substrate for investigation of the mechanism of yeast fatty acid synthase.
The acetyl transacylase activity of the fatty acid synthase from yeast has been investigated using p-nitrophenylthiol acetate. The chromophoric nature of the nitrophenylthiol moiety affords a convenient spectrophotometric assay for the transacylase function as well as a means to investigate the kinetics and the mechanism of this process. A probable kinetic scheme for enzyme catalyzed transacetylation from p-nitrophenylthiol acetate to an acyl acceptor (CoA or N-acetylcysteamine) is proposed and the kinetic constants for acetylation of enzyme and for acetyl transfer to an acceptor were determined. It was also demonstrated that p-nitrophenylthiol acetate can replace acetyl-CoA as a substrate in fatty acid synthesis.
D000105:Acetyl Coenzyme A / Q000378:metabolism; D002863:Chromogenic Compounds; D003065:Coenzyme A / Q000378:metabolism; D003543:Cysteamine / Q000031:analogs & derivatives / Q000378:metabolism; D064429:Fatty Acid Synthases / Q000378:metabolism*; D007700:Kinetics; D009596:Nitrophenols / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013053:Spectrophotometry
D002863:Chromogenic Compounds; D009596:Nitrophenols; C023704:2-acetamidoethanethiol; C046809:4-nitrophenylthiol acetate; D003543:Cysteamine; D000105:Acetyl Coenzyme A; D064429:Fatty Acid Synthases; D003065:Coenzyme A