Role of transmethylation reactions in alcoholic liver disease

Figure 1 Methionine metabolic pathway in the liver highlighting the importance of the methyltransferase-catalyzed reactions maintained by the cycling of the main participants, methionine, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) and homocysteine. The hepatocellular ratio of SAM to SAH is critical in controlling many transmethylation reactions.

Figure 2 Schematic of the effects of ethanol and betaine on transmethylation reactions. Overall, it had been determined the deleterious effects of ethanol on impaired transmethylation reactions can be prevented by betaine supplementation.