Abstract:[Objective] The alginate lyase gene of Pseudoalteromonas sp. BYS-2 was cloned and expressed in Escherichia coli, and the properties of recombinase were characterized. [Methods] The alginate lyase gene alg738 was cloned from the genomic DNA of Pseudoalteromonas sp. BYS-2 and the recombinant strain BL21(DE3)/pET22b-alg738 was constructed. The recombinase was purified with Ni-NTA resin and the enzymatic properties were studied. [Results] The optimum pH of recombinase was 8.0. It was stable in the pH range of 6.0 to 9.0 and could maintain more than 84% of its relative enzyme activity after incubation at 37 °C for 1 hour. The optimum temperature of recombinase was 45 °C and 66.6% of enzyme activity was remained after incubation at 37 °C for 60 minutes. At the concentration of 5 mmol/L, Na+, Mg2+ and Mn2+ had significant stimulation on the enzyme activity, while Ni2+, Co2+, Cu2+, Hg2+, Zn2+, EDTA, β-mercaptoethanol and SDS had inhibitory effects on the enzyme. The kinetic parameters Km and Vmax of rAlg738 were 1.11 g/L and 0.011 g/(L·min), respectively. Moreover, this recombinase was a bifunctional enzyme which prefers sodium polymannuronate (Poly M). [Conclusion] The properties of the recombinase rAlg738 has laid a good foundation for its future development and application.
