Fractionation of the pyruvate oxidase of Proteus vulgaris.

Cell-free extracts of Proteus vulgar& oxidize pyruvate to acetate and COS. By acid precipitation of such extracts, Stumpf (1) prepared a protein fraction that required cocarboxylase and certain divalent metal ions for activity; no requirement for phosphate or other acetyl acceptor system could be demonstrated. Thus the system resembled that of Escherichia coli described by Still (2), and differed from the phosphate-requiring Lactobacillus delbrueckii system (3). However, the recently described pyruvate dismutase of E. coli (4) requires phosphate or other acetyl acceptor system and coenzyme A (CoA). Ammonium sulfate fractionation of cell-free extracts of P. vulgaris has separated the pyruvate oxidase system into two heat-labile components which are required for activity (5). No evidence for the participation of CoA or acetyl CoA could be found. Recently, Korkes et al. (6) have separated the E. coli dismutase system into two protein components in addition to transacetylase and lactic dehydrogenase.