Cobalamin inactivation induces formyltetrahydrofolate synthetase

Loss of cobalamin function produces profound changes in the metabolism of formate. There is impaired synthesis of formyltetrahydropteroylglutamate synthetase (CHO-H 4,PteGlu), accumulation of endogenous formate and impaired utilization of [ 14C]formate. There are contradictory reports on the effect of cobalamin inactivation on CHO-H 4PteGlu synthetase. This study confirms a significant increase in synthetase activity following cobalamin inactivation.