描述

S-Adenosyl methionine (SAM-e) is a common cosubstrate involved in methyl group transfers, transsulfuration, and aminopropylation. Although these anabolic reactions occur throughout the body, most SAM-e is produced and consumed in the liver. More than 40 methyl transfers from SAM-e are known, to various substrates such as nucleic acids, proteins, lipids, and secondary metabolites. It is made from adenosine triphosphate (ATP) and methionine by methionine adenosyltransferase.

In bacteria, SAM-e is bound by the SAM riboswitch, which regulates genes involved in methionine or cysteine biosynthesis. In eukaryotic cells, SAM-e serves as a regulator of a variety of processes including DNA, tRNA, and rRNA methylation immune response amino acid metabolism transsulfuration, and more. In plants, SAM-e is crucial to the biosynthesis of ethylene, an important plant hormone, and signaling molecule.