(6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + NAD(+) = (6R)-5,10-methenyltetrahydrofolate + NADH
(6r)-5,10-methylene-5,6,7,8-tetrahydrofolate + nad(+) = (6r)-5,10-methenyltetrahydrofolate + nadh
(6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + NAD(+) = (6R)-5,10-methenyltetrahydrofolate + NADH
(6r)-5,10-methylene-5,6,7,8-tetrahydrofolate + nad(+) = (6r)-5,10-methenyltetrahydrofolate + nadh