Folate synthesis pathway

The **folate synthesis pathway** refers to the series of enzymatic reactions responsible for the de novo biosynthesis of folates—essential cofactors involved in one-carbon transfer reactions critical for nucleotide and amino acid metabolism. In bacteria, fungi, plants, and some protozoa, this pathway enables endogenous production of tetrahydrofolates from simple precursors. Humans cannot synthesize folates de novo; instead they rely on dietary intake. Folate coenzymes are required for the **synthesis of purines and thymidylate**, which are necessary for DNA replication and repair. They also participate in methylation cycles via methionine regeneration from homocysteine—a process essential for epigenetic regulation through S‐adenosylmethionine-mediated methylation. Disruption or inhibition of this metabolic route impairs cell division and is exploited therapeutically by drugs such as methotrexate or sulfonamides that target key enzymes like dihydrofolate reductase or dihydropteroate synthase. These agents are used as antimicrobials or anticancer drugs but can also cause toxicity due to effects on normal proliferating cells. **Note:** The "Folate synthesis pathway" is a *metabolic process*, not a single molecular target such as an enzyme or receptor. For drug development purposes, individual enzymes within this pathway—such as **dihydrofolate reductase**—are considered canonical therapeutic targets rather than the entire multi-step biochemical route itself. Therefore, "Folate synthesis pathway" should not be treated as a canonical molecular target; instead focus should be placed on its constituent enzymes when seeking structured information about drug targets.

Other names

Folate biosynthesis pathwayFolic acid synthesis pathwayOne-carbon metabolism (context-dependent)

Inhibition of dihydrofolate reductase (DHFR) to block tetrahydrofolate production (methotrexate, trimethoprim, pyrimethamine). Inhibition of dihydropteroate synthase to block folic acid precursor formation (sulfonamides).