摘要
Abstract
An ε - poly - L - Iysine - degrading enzyme of an ε - poly - L - lysine - producing strain of Streptomyces albulus ZC7 was purified and characterized. The enzyme was stable between pH 6. 0 and 8.0 with a maxinum at pH =7.0. The optimum temperature was 35℃, and no significant activity loss was observed when the enzyme was incubated at 20 ～40℃ for 30min. The effect of different metal ions on the activity of the enzyme were also investigated, some metal ions, including Zn2+ and Cu2+ , increased the enzyme activities by 34％ and 21％, respectively; while some other metal ions, including Co2+ , Mn2+ and Fe3+ , strongly inhibited the enzyme activity. The enzyme activity was not affected by Mg2+ and Ca2 +. Experiment results also showed that EDTA strongly inhibited the enzyme activity. The Km and Vmax values of ε - poly - L - lysine - degrading enzyme for ε - poly - L - lysine were 0. 226mmol/L and 0. 402 ×10-3 mmol/ (L · S), respectively. ε -Poly -L- lysine -degrading activity was found in the membrane fraction of some other Streptomyces strains as well as that of Streptomyces albulus, which exhibited high ε - poly - L - lysine - degrading activity. Both strains could produce ε - poly - L - lysine which indicating a correlation between the distribution of membrane - bound ε - poly - L - lysine - degrading enzyme and ε - poly - L - lysine - producing activity.关键词
ε-聚赖氨酸/白色链霉菌/ε-聚赖氨酸降解酶/酶学性质Key words
ε - Poly - L - lysine/ Streptomyces strains/ ε - poly - L - lysine -degrading enzyme/ property分类
生物科学
