STEREOCHEMICAL COURSE OF ACETATE ACTIVATION BY YEAST ACETYL-COA SYNTHETASE

Abstract

The purified .alpha.-thiophosphate diastereoisomers of adenosine 5''-(1-thio)-triphosphate were used to study the stereochemical course of the reaction catalyzed by yeast acetyl-CoA synthetase. Asymmetrically labeled adenosine 5''-thiophosphate was formed from the "B" diastereoisomer of adenosine 5''-(1-thio)-triphosphate and [18O]acetate. The label was in opposite orientation from the leaving pyrophosphate group showing that the acetate activation step occurred with inversion of configuration at the .alpha.-phosphorus.