FIELD: chemistry.
SUBSTANCE: group of inventions relates to biotechnology, particularly to mutant O-phosphoserine sulfhydrylase (OPSS) from Mycobacterium smegmatis with an amino acid sequence corresponding to SEQ ID NO: 1 which is devoid of three to seven C-terminal amino acid residues. The inventions also relate to a nucleic acid molecule encoding the mutant OPSS, an expression vector carrying the nucleic acid molecule, and a transformant transformed by the expression vector. In addition, a method is provided for producing cysteine in which O-phospho-L-serine (OPS) is reacted with a sulphide in the presence of the mutant OPSS.
EFFECT: muntant OPSS has improved enzymatic activity and can be used for environmentally friendly production of L-cysteine in conditions through a simple enzymatic conversion reaction; the group of inventions provides high output of L-cysteine.
16 cl, 7 dwg, 20 tbl, 19 ex
