Folate-dependent cofactor pool

The folate-dependent cofactor pool is a collection of tetrahydrofolate (THF) derivatives that function as essential carriers of one-carbon units for various biosynthetic processes [1]. These cofactors, including 10-formyl-THF and 5,10-methylene-THF, are indispensable for the de novo synthesis of purines and thymidylate, which are required for DNA replication and cellular repair [2]. Beyond nucleotide synthesis, the pool plays a vital role in the methionine cycle, providing methyl groups for the methylation of DNA, RNA, and proteins [3]. Because rapidly dividing cells have a high demand for these cofactors, the folate pool is a major focus in oncology and rheumatology [4]. Therapeutic agents known as antifolates, such as methotrexate and pemetrexed, work by inhibiting key enzymes like dihydrofolate reductase (DHFR) or thymidylate synthase (TS), effectively depleting the pool of active reduced folates [3, 4]. This depletion leads to the cessation of DNA synthesis and eventual cell death, particularly in malignant tissues [2]. Clinical management of this pool also involves the use of leucovorin to bypass metabolic blocks and reduce toxicity in healthy tissues [4]. Deficiencies in this pool are linked to megaloblastic anemia and developmental issues such as neural tube defects [1, 2].

Other names

Folate cycleOne-carbon metabolismReduced folate poolTetrahydrofolate poolFolate-mediated one-carbon metabolism

Inhibition of enzymes within the folate cycle (e.g., DHFR, TS) to deplete the availability of reduced folate cofactors required for nucleotide synthesis and methylation.