An iron-sulfur flavoprotein that also contains zinc. The enzyme from Clostridium formicoaceticum catalyses the reduction of methylene blue, menadione, benzyl viologen, rubredoxin or FAD with 5-methyltetrahydrofolate and the oxidation of reduced ferredoxin or FADH2 with 5,10-methylenetetrahydrofolate. However, unlike EC 220.127.116.11, methylenetetrahydrofolate reductase [NAD(P)H], there is no activity with NAD(P)H.
Clark, J.E. and Ljungdahl, L.G. Purification and properties of 5,10-methylenetetrahydrofolate reductase, an iron-sulfur flavoprotein from Clostridium formicoaceticum. J. Biol. Chem.259 (1984) 10845–10849. [PMID: 6381490]