DEGRADATION OF PYRUVATE BY MICROCOCCUS LACTILYTICUS II. : Studies of Cofactors in the Formate-Exchange Reaction

Abstract

McCormick, N. G. (University of Washington, Seattle), E. J. Ordal, and H. R. Whiteley. Degradation of pyruvate by Micrococcus lactilyticus. II. Studies of cofactors in the formate-exchange reaction. J. Bacteriol. 83:899-906. 1962.-Enzyme preparations from Micrococcus lactilyticus(2) are rendered inactive with respect to formate exchange by treatment with charcoal or Dowex-50, by dialysis, or by fractionation with ammonium sulfate. The activity may be completely restored by a "kochsaft" preparation (BES) obtained from M. lactilyticus and partially restored by similar BES preparations from Escherichia coli and Clostridium butyricum. Diphosphothiamine is required for formate exchange but full activity cannot be restored by known cofactors. Brief exposure to increased temperatures, air, extremes of pH, and absorption with charcoal and Dowex-50 decrease the cofactor activity of BES preparations. The addition of BES preparations from E. coli and Streptococcus faecalis causes a shift in the degradation of pyruvate by extracts of M. lactilyticus from the phosphoroclastic cleavage (to acetyl phosphate and formate) to the dismutation of pyruvate (to lactate, acetate, and carbon dioxide).C. cylindrosporum was found to mediate the formate-exchange reaction; the activity of crude extracts was stimulated by M. lactilyticus and C. butyricum BES preparations. M. lactilyticus BES also increased the formate-exchange activity of extracts of E. coli.