Thiol S-methyltransferase that catalyzes the transfer of a methyl group from S-adenosyl-L-methionine to alkyl and phenolic thiol-containing acceptor substrates. Together with TMT1B accounts for most of S-thiol methylation activity in the endoplasmic reticulum of hepatocytes. Selectively methylates S-centered nucleophiles from metabolites such as hydrogen sulfide and dithiothreitol.
Subcellular locations: Endoplasmic reticulum membrane, Lipid droplet, Microsome, Cytoplasm, Cytosol
Highly concentrated in the perinuclear area of the endoplasmic reticulum (ER) and surrounding lipid droplets. May be associated with the specific regions of the LR that form lipid droplets and targeted to the initial deposits of lipids where the lipid droplets form.
Expressed in the liver.