硝基还原假单胞菌谷氨酰胺酶的分离纯化及酶学性质

摘要

Glutaminase from Pseudomonas nitroreducens SK16. 004 was purified by ion-exchange and gel filtration chromatography. The characteristics and Km of the enzyme were studied. The result showed that the optimal reaction temperature and pH of purified glutaminase were 551 and 9. 0, respectively. It was stable within range of pH value from 5. 0 to 11. 0 under 371 to 60℃. The enzyme was greatly activated by Cu2+ and partly inhibited by Fe3 + . It exhibited the highest affinity to glutamine and its Km and Vmax were 0. 72 mmol/L and 0. 55 μmol/(min · mL) , respectively.%采用离子交换层析和凝胶过滤层析等方法,分离纯化硝基还原假单胞菌(Pseudomonas nitroreducens)SK16.004所产的谷氨酰胺酶,并进一步研究该酶的酶学性质及反应动力学参数.结果表明,该酶的最适反应温度为55℃,最适pH为9.0,温度稳定范围为37～60℃,pH稳定范围为5.0～11.0;Cu2+对促进酶活提高作用最大,而Fe3+会抑制该酶的转移活力.谷氨酰胺酶对底物谷氨酰胺的亲和力最强,其Km值为0.72 mmol/L,Vmax为0.55 μmol/(min·mL).