Reaction catalyzed by methylenetetrahydrofolate reductase [NAD(P)H] (1.5.1.20), methylenetetrahydrofolate reductase (NADPH) (1.5.1.53)
+
oxidized menadione
=
+
5-methyltetrahydrofolate
+
oxidized menadione
=
5,10-methylenetetrahydrofolate
+
reduced menadione