Monofunctional C1-tetrahydrofolate synthase, mitochondrial also known as formyltetrahydrofolate synthetase, is an enzyme that in humans is encoded by the MTHFD1L gene (methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1-like).

Function

One-carbon substituted forms of tetrahydrofolate (THF) are involved in the de novo synthesis of purines and thymidylate and support cellular methylation reactions through the regeneration of methionine from homocysteine. MTHFD1L is an enzyme involved in THF synthesis in mitochondria. In contrast to MTHFD1 that has trifunctional methylenetetrahydrofolate dehydrogenase, methenyltetrahydrofolate cyclohydrolase, and formyltetrahydrofolate synthetase enzymatic activities, MTHFD1L only has formyltetrahydrofolate synthetase activity.

Clinical significance

Certain variants of the MTHFD1L are associated neural tube defects. Different alleles of SNP rs7646 in the 3′ UTR of MTHFD1L are differentially regulated by microRNAs affecting MTHFD1L expression.