Figure 1. Scheme of the folate-homocysteine pathway (MTX = methotrexate; MTXPG = MTX polyglutamates; DHFR = dihydrofolate reductase; DHF = dihydrofolate; THF = tetrahydrofolate; 5-MTHF = 5-methyl-THF; 5,10-MTHF = 5,10-methylene-THF; HCY = homocysteine; MS = methionine synthase; SAM = S-adenosylmethionine; SAH = S-adenosylhomocysteine).
