硝基还原假单胞菌谷氨酰胺酶的分离纯化及酶学性质

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0.55μmol/(min.mL)。

Purification and Characterization of Glutaminase from Pseudomonas nitroreducens

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 55℃ and 9.0,respectively.It was stable within range of pH value from 5.0 to 11.0 under 37℃ 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.