Acetate kinase from Veillonella alcalescens. Purification and physical properties.

Acetate kinase (ATP:phosphotransferase E.C.2.7.2.1) has been purified to a high state of purity from Veillonella alcalescens. The native enzyme had a molecular weight of 88,000, as determined by Sephadex G-150 gel filtration. The molecular weight of the monomeric enzyme, estimated from sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was 42,000. The enzyme was determined to be a homodimer from the amino acid composition and the results of trypsin digestion and cyanogen bromide cleavage. Two moles of phosphate were incorporated into the dimer upon incubation of the enzyme with ATP and acetate. These results support the conclusion that each subunit of the dimeric enzyme consists of a single active catalytic center. Succinate enhanced the rate of ATP-ADP phosphoryl group exchange 20-fold and the binding of ATP 10-fold. These results are considered in light of data from previous reports (Pelroy, R. A., and Whiteley, H. R. (1971) J. Bacteriol. 105, 259-267; Bowman, C. M., Valdez, R. O., and Nishimura, J. S. (1976) J. Biol. Chem 251, 3117-3121).