Studies of the acetyl coenzyme A synthetase reaction. IV. The requirement for monovalent cations.

Acetyl coenzyme A synthetase, which catalyzes the biosynthesis of acetyl coenzyme A from acetat,e, adenosine triphosphate, and coenzyme A, has previously been obtained in highly purified form from bovine heart mitochondria (1). The enzyme appeared to be fairly homogeneous because only a single protein peak was detected in two chromatographic systems and the pattern observed in the analytical ultracentrifuge showed only minor contamination. However, the preparative procedure was lengthy and difficult to reproduce. Now, crystalline acetyl-CoA synthetase has been obtained which shows a specific activity over twice that found previously. This report describes the improved fractionation procedure and certain properties of the purified enzyme including its molecular weight.