Equilibrium constant for conversion of pyruvate to acetyl phosphate and formate.

Preparations of pyruvate formate-lyase were made from Escherichia coli cells. Net reversal of the "phosphoroclastic split" of pyruvate was readily demonstrated with these preparations. Incubation of acetyl phosphate with formate resulted in the accumulation of pyruvate in concentrations up to 0.5 mm. Catalytic amounts of coenzyme A were essential. Pyruvate was also readily formed from acetyl coenzyme A and formate. The equilibrium constant of the reaction (pyruvate(-) + HPO(4) (2-) --> acetyl phosphate(2-) + formate(-)) has been determined to be about 23 at 37 C.