Serine acetyltransferase which catalyzes the formation of O-acetyl-L-serine from acetyl-CoA and L-serine (PubMed:7851429, PubMed:9830017). Also displays O-acetylserine (thio1)-lyase activity in vitro (PubMed:7851429). May be involved in detoxification process by mediating the production of glutathione. acetyl-CoA + L-serine = CoA + O-acetyl-L-serine Amino-acid biosynthesis; L-cysteine biosynthesis; L-cysteine from L-serine: step 1/2. Homomultimer (By similarity). Interacts with OASA1 and CYP20-3. Component of the cysteine synthase complex (CSC) composed of two OAS-TL dimers and one SAT hexamer. First chloroplastic and progressively cytoplasmic during aging. Mostly expressed in leaves. Localized in cortex, trichomes and vascular tissues, particularly in phloem. By cadmium (Cd). Not induced under sulfur-deficient conditions. Repressed in trichomes in response to NaCl treatment. Belongs to the transferase hexapeptide repeat family.