枯草芽孢杆菌TM903嘌呤核苷磷酸化酶的纯化及酶学性质研究

目的：对枯草芽孢杆菌TM903嘌呤核苷磷酸化酶进行分离纯化及酶学性质研究。方法：经加热、硫酸铵盐析和SephadexG-100凝胶过滤，对枯草芽孢杆菌TM903中的嘌呤核苷磷酸化酶进行分离纯化，并对其酶学性质进行研究。结果：酶的最适反应温度为65℃，最适反应pH值为7．5，在30-50℃时热稳定性较好；K^＋对该酶有激活作用，而Na^＋、ca^＋、Mg^＋、Mn^＋等金属离子对该酶有抑制作用；Km值为2．11mmol／L，Vmax值为0．84mmol／（min·L）。结论：分离纯化了枯草芽孢杆菌TM903嘌呤核苷磷酸化酶，并研究了其酶学性质，为利巴韦林的发酵工艺优化提供了重要的酶学理论基础。

Purification and Characterization of the Purine Nucleoside Phosphorylase from Bacillus subtilis TM903

Objective： To isolate, purify and characterize the purine nucleoside phosphorylase（PNPase） from Bacillus subtilis TM903. Methods： By a multistep procedure including heating, ammonium sulfate precipitation, and chromatography on Sephadex G-100, some properties of PNPase were further studied. Results： The results showed that the optimum temperature and pH was 65℃ and 7.5, respectively. It was extremely stable in the temperature range from 30℃ to 50℃. In addition, K^＋ could stimulate PNPase activity, whereas Na^＋, Ca^2＋, Ms^2＋ and Mn^2＋ inhibit. The kinetic analysis revealed that the value of Km and Vmax was 2.11 mmol/L and 0.84 mmol/（min-L）, respectively. Conclusion： The data obtained in this study should provide an important reference for condition optimization of ribavirin fermentation.