Ii. Enzymatic Synthesis of Formyl Phosphate and Formyl Coenzyme a in Clostridi Um Cylindrosporum

It was incidentally observed in this laboratory that crystalline preparations of formyltetrahydrofolate synthetase from CEostridium cylindrosporum catalyze the activation of formate by adenosine triphosphate in the absence of tetrahydrofolate. Efforts to determine whether the tetrahydrofolate-independent reaction is catalyzed by formyltetrahydrofolate synthetase led eventually to the discovery of two formate kinases in extracts of C. cylindrosporum which catalyze the formation of formyl phosphate. It was further established that formyl phosphate serves as a formyl donor for the synthesis of formyl coenzyme A in a reaction catalyzed by phosphate acetyltransferase. It is the purpose of this communication to summarize the results of these experiments.