InterPro domain: IPR005881

The biosynthesis of L-cysteine is the predominant way by which inorganic sulphur is incorporated into organic compounds. In this process, the most abundant utilizable source of sulphur, inorganic sulphate, is taken up and reduced to sulphide. Sulphide is used to produce L-cysteine, which serves for protein synthesis or the production of other sulphur-containing organic compounds. Two routes for cysteine biosynthesis in nature have been documented. Serine transacetylase (also known as serine O-acetyltransferase; 2.3.1.30 ) catalyzes steps in pathway I, the activation of L-serine by acetyl-coenzyme A, yielding O-acetyl-L-serine.