metytransferaser

Metytransferase, more commonly known in English as methyltransferase, is a broad class of enzymes that catalyze the transfer of a methyl group from S-adenosyl-L-methionine (SAM) to diverse substrates. The reaction typically converts SAM to S-adenosyl-L-homocysteine (SAH) and yields a methylated product. Metytransferases act on a wide range of targets, including DNA, RNA, proteins, and small molecules, and they play key roles in regulation, metabolism, and biosynthetic pathways.

Major subclasses include DNA methyltransferases that methylate cytosine or adenine residues, RNA methyltransferases that modify ribosomal RNA, transfer RNA, or mRNA, protein methyltransferases that alter lysine, arginine, or other amino acids, and small-molecule methyltransferases that modify metabolites. Each subclass exhibits distinct substrate specificities and cellular roles, reflecting the diversity of methylation chemistry in biology.

Mechanistically, most metytransferases utilize SAM as the methyl donor and employ catalytic residues and structural motifs tailored to their substrates. Structural folds vary among families, but many share folds that support nucleotide or amino acid binding and precise positioning of the methyl donor and acceptor.

Biological and practical relevance is broad. DNA methyltransferases contribute to epigenetic regulation and genome defense; RNA and protein methyltransferases modulate stability, translation, and signaling; small-molecule methyltransferases influence metabolism and drug handling. In medicine and biotechnology, methyltransferases are targets for cancer therapies and tools for labeling, modification, and biosynthesis.

Examples include human DNA methyltransferases DNMT1, DNMT3A, and DNMT3B; RNA and protein methyltransferases such as TRMT1 and PRMT1; and metabolic enzymes like COMT and TPMT.