DEGRADATION OF PYRUVATE BY MICROCOCCUS LACTILYTICUS II

McCormick , N. G. (University of Washington, Seattle), E. J.Ordal, and H. R. Whiteley . Degradation of pyruvate byMicrococcus lactilyticus . II. Studies of cofactors in the formate-exchange reaction. J. Bacteriol.83: 899–906. 1962.—Enzyme preparations fromMicrococcus 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 fromM. lactilyticus and partially restored by similar BES preparations fromEscherichia coli andClostridium 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 fromE. coli andStreptococcus faecalis causes a shift in the degradation of pyruvate by extracts ofM. 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 byM. lactilyticus andC. butyricum BES preparations.M. lactilyticus BES also increased the formate-exchange activity of extracts ofE. coli .