Expression and characterization of a chitinase from Serratia marcescens.

Jincheng Li, Jiamin Zheng, Yanhui Liang, Renxiang Yan, Xinqi Xu, Juan Lin

Protein expression and purification 2020 Jul

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A chitinase gene from Serratia marcescens was cloned and expressed in Escherichia coli BL21(DE3) and the properties of recombinant chitinase rCHI-2 were characterized. The optimum catalytic pH of rCHI-2 was 6.0. It was stable in the pH range of 6.0-9.0 and could maintain more than 90% of its relative enzyme activity after incubation at 37 °C for 1 h. The optimum catalytic temperature of the enzyme was 55 °C and 85% of enzyme activity was remained after incubation at 45 °C for 1 h. The activation energy of the thermal inactivation of the enzyme was 10.9 kJ/mol and the Michaelis-Menten constant was 3.2 g/L. The purified rCHI-2 was found to be highly stable at 45 °C with half-life (t1/2) of 289 min and thermodynamic parameters ΔH*, ΔG* and ΔS* revealed high affinity of rCHI-2 for chitin. Hg2+ was found to be able to inhibit the enzyme activity reversibly, while IC50 and inhibition constant of Hg2+ on the enzyme were 34.8 μmol/L and 44.6 μmol/L, respectively. Moreover, rCHI-2 could specifically hydrolyze colloidal chitin into GlcNAc2 as the major product. Copyright © 2020 Elsevier Inc. All rights reserved.

Citation

Jincheng Li, Jiamin Zheng, Yanhui Liang, Renxiang Yan, Xinqi Xu, Juan Lin. Expression and characterization of a chitinase from Serratia marcescens. Protein expression and purification. 2020 Jul;171:105613