Lablog4-13:Cloning, overexpression, purification, and characterization of O-acetylserine sulfhydrylase-B from Escherichia coli

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Chunhui Zhao, Yoichi Kumada, Hiroyuki Imanaka, Koreyoshi Imamura, Kazuhiro Nakanishi

First author

Chunhui Zhao

Corresponding author

Kazuhiro Nakanishi

Publication Style

Journal name Protein expression and purification


Volume, issue, pages

 47(2) 607-13


O-Acetylserine sulfhydrylase-B (OASS-B, EC is one of the two isozymes produced by Escherichia coli that catalyze the synthesis of l-cysteine from O-acetyl-l-serine and sulfide. The cysM gene encoding OASS-B was cloned and the enzyme was overexpressed in E. coli using pUC19 with a lacUV5 promoter. The enzyme was purified to homogeneity, as evidenced by SDS–PAGE. Approximately 300 mg of purified OASS-B was obtained from 1600 mL of culture broth with a purification yield of 60% or higher. The purified OASS-B was characterized and its properties compared with OASS-A. OASS-B did not form a complex with E. coli serine acetyltransferase (SAT, EC and showed a wide range of substrate specificity in nonproteinaceous amino acid synthesis.