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| Oligopeptidase B (OpdB) of Escherichia coli, previously called protease Ⅱ, has a trypsin-like specificity, cleaving peptides at lysine and arginine residues and belongs to the prolyl oligopeptidase family of new serine peptidases. In this study, we report the fusion expression of E. coli oligopeptidase B with an N-terminal histidine tag using pET28a as the expression vector. The homogeneity and activity of the purified OpdB were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and enzymatic activity assay, respectively. We also compared the substrate specificity of the purified OpdB for some synthetic trypsin substrates with those of OpdA, another trypsin-like protease in E. coli. The availability of large amount of the recombinant OpdB will facilitate the biological functional study of this enzyme. |
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| Keywords: Escherichia coli; Oligopeptidase B; Trypsin-like protease; Fusion expression |
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