Folate is a cofactor required for the synthesis of glycine, allowing the conversion of dUMP to dTMP. This is the main route to synthesise glycine, so insufficient folate will lead to glycine deficiency.
Folate, when in its carrier molecule, can be reduced or oxidised, forming dihydrofolate and tetrahydrofolate. This can be catalysed by dihydrofolate reductase, converting dihydrofolate to tetrahydrofolate. This is an important process in DNA synthesis, with inhibitors, such as methotrexate, being used as chemotherapy drugs. Methotrexate inhibits folic acid activity, preventing nascent DNA production, and thus slowing the growth of tumours. Some antibiotics also inhibit folic acid’s activity, with trimethoprim inhibiting bacterial DNA synthesis.