Expression and characterization of a chitinase from Serratia marcescens

Publication date: Available online 23 February 2020Source: Protein Expression and PurificationAuthor(s): Jincheng Li, Jiamin Zheng, Yanhui Liang, Renxiang Yan, Xinqi Xu, Juan LinAbstractA chitinase gene from Serratia marcescens was cloned and expressed in Escherichia coli 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.

Source: Protein Expression and Purification - February 24, 2020 Category: Biochemistry Source Type: research