S-adenosylmethionine (SAM)

S-adenosylmethionine (SAM) is a naturally occurring sulfonium compound formed from methionine and ATP. It is the principal biological methyl donor, essential for over 40 methylation reactions involving nucleic acids, proteins, lipids, and secondary metabolites. Most SAM is synthesized and consumed in the liver, where it plays key roles in transmethylation, transsulfuration, and aminopropylation, influencing processes such as gene expression, detoxification, and antioxidant defense. Commercially, it is known as SAMe and used as a dietary supplement. SAM's therapeutic use has been explored in liver disease, depression, and osteoarthritis, but clinical benefits remain inconclusive, and its long-term safety profile has not been fully established. SAM is not itself a drug target (e.g., receptor, enzyme, transporter), but rather a coenzyme and metabolite; enzymes that synthesize or utilize SAM are the actual molecular targets in drug discovery and pharmacology.

Other names

SAMeSAM-eAdoMetS-adenosyl-L-methionineAdemetionineMethionine,activeS-(5'-Adenosyl)methionine

Serves as a methyl donor in transmethylation reactions, Essential for the synthesis of cysteine and glutathione, Involved in the regulation of membrane lipid methylation