Overview of folate and methionine metabolic pathways. TYMS binds methylenetetrahydrofolate (5,10-methylene THF), which serves as a hydroxymethyl donor in the conversion of dUMP to dTMP in the DNA synthesis pathway. SHMT catalyzes the reversible conversion of serine and THF to glycine and methylene THF. MTHFR catalyzes the reduction of 5,10-methylene THF to 5-methyl THF. MTR catalyzes the transfer of methyl base from 5-methyl THF to homocysteine. Adapted From Matsuo et al15 with permission.