Figure 2.

One-carbon metabolism. This figure shows the main components of the one-carbon metabolism, the folate cycle, the methionine cycle, and the contribution of micronutrients such as choline, betaine, folate, methionine, VitB6, and VitB12 in several biological processes. Enzymes and vitamins are written in red and biological processes are highlighted in green. Micronutrients are highlighted in blue. THF: tetrahydrofolate, SAM: S-adenosylmethionine, SHA: S-adenosylhomocysteine, SAHH: SAH hydrolase, BHMT: betaine-homocysteine methyltransferase, MAT: methionine acetyltransferase, DNMTs: DNA methyltransferases, HMTs: histone methyltransferases, MS: methionine synthase, MTHFR: methyltetrahydrofolate reductase, ChAT: choline acetyltransferase, AchE: acetylcholine esterase, GSH: glutathione. Adapted from Ref. [5].