Study the effect of His-tag on chondroitinase ABC I based on characterization of enzyme

Chondroitinase ABC I (ChSase ABC I) which could degrade chondroitin sulfate (CS) to low molecular weight CS was expressed with His-tag in Escherichia coli (E. coli) BL21(DE3). The effect of His-tag on ChSase ABC I was investigated compared with ChSase ABC I which cut His-tag for the first time. After three steps purification, the specific activity of His-ChSase ABC I was 201.9 +/- 5.4 IU/mg which was two times lower than ChSase ABC I. Results of multi angle light scattering (MALS) and analytical ultracentrifugation (AUC) showed that the polymeric state of His-ChSase ABC I was not effected by His-tag and it was monomer, and ChSase ABC I was the same. The optimal temperature and pH of His-ChSase ABC I were 37 degrees C and 7.5, and were almost same with ChSase ABC I. V-max and k(cat)/K-m of His-ChSase ABC I were 2.4 +/- 0.1 mu mol/Ls, and 22.2 +/- 0.4 L/(mu mol s) and catalytic efficiency was lower than ChSase ABC I. Generally, His-tag had no effect on polymeric state, optimal temperature and pH, had little negative impact on specific activity, k(cat)/K-m and secondary-structure of ChSase ABC I. This study might guide the application of ChSase ABC I in industrial production. (C) 2015 Elsevier B.V. All rights reserved.