An enzyme, phosphotransacetylase [acetyl-CoA: orthophosphate acetyltransferase, EC 2.3.1.8], which catalyzes the reversible transfer of an acetyl group from acetyl Coenzyme A to phosphate, was isolated from extracts of Lactobacillus fermenti strain 36, IFO No. 3071 (ATCC No. 9338). 2. The purest preparation of phosphotransacetylase with a specific activity of 1, 124 μmoles per min per mg protein appeared almost homogeneous on polyacrylamide disc electrophoresis. 3. The enzyme has a molecular weight of 68, 000 estimated by gel filtration. The elution pattern of the enzyme on Sephadex G-150 gel filtration was quite similar to that of Clostridium phosphotransacetylase. 4. The enzyme has its maximum activity at pH 7.6 in Tris-HCl buffer. 5. The Km value for Coenzyme A was estimated as 8.7×l0−5M. 6. The enzyme has an isoelectric point at pH 4.1 estimated by the ampholine electro-focussing method. 7. NH4+, K+, and Rb+ are required for maximum activity, but Ca2+, Mg2+, Ba2+, Li+, Cs+, and SO42− are inhibitory. EDTA, NAD+, and NADH have not appreciable effects. 8. The equilibrium constant for acetylation of Coenzyme A was estimated to be 134±20 at 27°C, pH 7.6.
No takes yet. Share an insight, caveat, or question.
Nojiri et al. (1971) studied this question.