Methylenetetrahydrofolate Reductase - Biochemistry

Biochemistry

MTHFR irreversibly reduces 5,10-methylenetetrahydrofolate (substrate) to 5-methyltetrahydrofolate (product).

• 5,10-methylenetetrahydrofolate is used to convert dUMP to dTMP for de novo thymidine synthesis.
• 5-Methyltetrahydrofolate is used to convert homocysteine (a potentially toxic amino acid) to methionine by the enzyme methionine synthase. (Note that homocysteine can also be converted to methionine by the folate-independent enzyme betaine-homocysteine methyltransferase (BHMT))

MTHFR contains a bound flavin cofactor and uses NAD(P)H as the reducing agent.