Fig. 3

Polyacrylamide gel electrophoresis (PAGE) analysis of chitinases from C. meiyuanensis SYBC-H1 and recombinant E. coli BL21(DE3). a SDS-PAGE analysis of the expression and purification of recombinant CmChi1. The amount of protein applied to the gel is 10 μg Lane M, protein molecular mass markers; lane 1, total protein of recombinant Escherichia coli BL21(DE3); lane 2, extract of a 50-mM imidazole eluted sample from a Ni–NTA column; lane 3, extract of a 200-mM imidazole eluted sample from a Ni–NTA column; lane 4, eluted sample using 1 M NaCl from the complex containing CC and CmChi1; lane 5, digestion extract without reducing sugar from the complex containing CC and CmChi1. b Zymogram analysis of purified recombinant CmChi1 by a native PAGE. The left gel slice is the coomassie stained one and that on the right is the zymogram. The zymogram assay was conducted in 50 mM sodium citrate buffer (pH 5.2) containing 0.5 mM 4-methylumbelliferyl N,N′-diacetyl-β-d-chitobioside (4-MU-[GlcNAc]₂) at 37 °C for 30 min, then placed at 340 nm for showing fluorescence