Thiol methyltransferase 1B (TMT1B)

Thiol methyltransferase 1B (TMT1B), more commonly known as METTL7B or methyltransferase-like protein 7B, is an enzyme of the methyltransferase family that catalyzes S-methylation of alkyl thiols using S-adenosyl-L-methionine as a methyl donor[1][2][4]. It is membrane-associated, localizing mainly to the endoplasmic reticulum and lipid droplets, and displays broad substrate specificity for exogenous thiol-containing small molecules but not for endogenous thiols such as cysteine or glutathione[1][2]. TMT1B is increasingly recognized for its upregulation in several cancers, where its expression correlates with tumor progression, migration, invasion, and poor prognosis, making it a potential oncogenic biomarker and target[4][5]. The enzyme also appears to play a role in hydrogen sulfide metabolism, cellular redox balance, and possibly inflammation, though its full physiological role remains incompletely understood[2][3][4]. No specific inhibitors are currently used clinically, but altered TMT1B levels may influence the metabolism and effects of certain thiol-containing drugs[1].

Other names

METTL7BMethyltransferase-like protein 7BThiol S-methyltransferase METTL7BAssociated with lipid droplets 1ALDIUNQ594/PRO1180MGC17301

SAM-dependent methyl transfer (using S-adenosyl-L-methionine as methyl donor) to alkyl thiols, including drug metabolites and potentially hydrogen sulfide (H₂S)[1][2][4]