气单胞菌属JH菌株脂肪酶酶学特性的研究

从JH菌体中提取脂肪酶，并在不同的反应条件下对其酶学性质进行研究。该脂肪酶最佳反应温度和缓冲液pH制分别为40℃和7．0。该酶具有较强的热稳定性和pH稳定性：经过30℃、40℃处理60rain仍然保持90％以上的酶活；用pH3．5～9缓冲液处珲该酶，仍然保持80％以上的酶活。Ca2＋、Mg2＋对该脂肪酶具有明显的激活作用，尤其是Mg2＋作用最为显著，与对照组相比提高了38．8％，Zn2＋、Fe2＋对该脂肪酶有显著的抑制作用，Cu2＋对脂肪酶的影响不显著。用双倒数法作图得到Vmax=2．13×10^-2mol／L，Km=0．639（mmol／mL）min-1。表面活性剂吐温-80对脂肪酶有促进作用。该菌株产生的脂肪酶町以往温和的反应条件下作用。

Characterization of lipase from Aeromonas sp. JH

The lipase was extracted from Aeromonas sp. JH, and its enzymatic properties under the different reaction conditions were studied. The optimum temperature and pH for enzyme reaction were 40℃ and pH 9. 0, respectively. The enzyme activity retained more than 90% when the lipase was treated at 30℃ and 40℃ for 60 min, and retained more than 80% when the lipase was treated in pH 3. 5-9 buffer. The lipase was activated by Ca2+ and Mg2+ remarkably, especially for Mg2+, by which the lipase activity was enhanced 38. 8% compared with the control. The lipase was inhibited by Zn2+ and Fe2+. And the activity had no much change by Cu2+ . By double reciprocal painting, the Vmax and Km of the lipase were confirmed as 2. 13×10-2 mol/L and 0. 639 (mol/L) min-1, respectively. The lipase was activated by Tween-80. The lipase from Aeromonas sp. JH could react under moderate conditions.