Characterization of Recombinant PolyG-Specific Lyase from a Marine Bacterium, Streptomyces sp. M3

A new alginate lyase gene of marine bacterium Streptomyces sp. M3 had been previously cloned in pColdI vector and transformed into E. coli BL21 (DE3). In this study, M3 lyase protein without signal peptide was overexpressed by induction with IPTG and purified with Ni-Sepharose affinity chromatography. The absorbance at 235 nm of the reaction mixture and TLC analysis showed that M3 alginate lyase was a polyG-specific lyase. When M3 lyase was assayed with substrate for 10 min, optimum pH and optimum temperature were pH 9 and 60℃. For the effect of 1mM metal ion on M3 lyase activity, Ca++ and Mn++ ions increased the alginate degrading activity by two-fold, whereas Hg++ and Zn++ ions inhibited the lyase activity completely. Mg++, Co++, Na+, K+, and Ba++ did not show any strong effects on alginate lyase activity.