Schematic of the folate futile cycle (adapted from reference 35).

5-formyltetrahydrofolate (5-formylTHF); methenyltetrahydrofolate synthetase (MTHFS); methenyltetrahydrofolate (methenylTHF); 5,10-methylenetetrahydrofolate (methyleneTHF); cytosolic serine hydroxymethyltransferase (cSHMT); tetrahydrofolate (THF).