ABSTRACT
Biologically active folate is not folic acid itself but its reduced metabolite tetrahydrofolate (THF). THF acts as a carrier of one-carbon units in biochemical reactions that lead to the synthesis of the purines (adenine and guanine) and one of the pyrimidines (thymine), which are the base constituents of DNA. In another important reaction, 5-methyl-THF donates its methyl group to homocysteine to form methionine.
