O Acetylserine

O-Acetylserine is the α-amino acid with the chemical formula HO₂CCH(NH₂)CH₂OC(O)CH₃. It is an intermediate in the biosynthesis of the common amino acid cysteine in bacteria and plants. O-Acetylserine is biosynthesized by acetylation of the serine by the enzyme serine transacetylase. The enzyme O-acetylserine (thiol)-lyase, using sulfide sources, converts this ester into cysteine, releasing acetate:

HO₂CCH(NH₂)CH₂OH → HO₂CCH(NH₂)CH₂OC(O)CH₃ HO₂CCH(NH₂)CH₂OC(O)CH₃ → HO₂CCH(NH₂)CH₂SH