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从山东省莱州海区自然发病的花鲈 (Lateolobraxjapanicus)体内分离到 1株致病性鳗弧菌 ,经硫酸铵盐析、DEAE SepharoseFastFlow和Sephadex G10 0凝胶层析等方法从其培养液中分离纯化了 1种胞外蛋白酶。用SDS PAGE电泳测得蛋白质的分子量为 36 7kD ,酶的最适温度为 5 0℃ ,对热不稳定 ,70℃ 15min完全失去活力 ;最适pH为 7 0 ;1mmol/L的PMSF对酶活性无影响 ,部分金属离子如Cu2 + 、Fe2 + 、Fe3 + 、Zn2 + 对酶活力有抑制作用 ,而Ca2 + 对酶有一定程度的激活作用 ,1mmol/LEDTA能完全抑制酶的活性 ,表明该酶是 1种金属蛋白酶
One pathogenic Vibrio anguillarum was isolated from the naturally occurring Japanese sea bass (Lateolobraxjapanicus) in Laizhou, Shandong Province. The pathogenic Vibrio anguillarum was isolated and purified from its culture medium by ammonium sulfate salting-out, DEAE SepharoseFastFlow and Sephadex G10 0 gel chromatography One extracellular protease. The SDS-PAGE electrophoresis showed that the molecular weight of the protein was 36 7 kD, the optimum temperature of the enzyme was 50 ℃, the activity of the enzyme was completely lost to heat-labile and 70 ℃ for 15 min; the optimum pH was 70; No effect. Some metal ions such as Cu2 +, Fe2 +, Fe3 + and Zn2 + inhibited the activity of the enzyme, while Ca2 + activated the enzyme to a certain extent. The activity of 1mmol / LEDTA was completely inhibited, indicating that the enzyme Is a kind of metallo protease