The stereochemical course of acetate activation by yeast acetyl-CoA synthetase

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 found to be in the opposite orientation from the leaving pyrophosphate group showing that the acetate activation step occurred with inversion of configuration at the alpha-phosphorus.