高校化学工程学报2011，Vol.25Issue(1)：85-90,6.
Ca2+对枯草芽孢杆菌γ-谷氨酰转肽酶活性和热稳定性的影响
Effects of Ca2+ on the Activity and Thermal Stability of γ-Glutamyltranspeptidase from Bacillus Subtilis
摘要
Abstract
The γ-glutamyltranspeptidase (GGT) can be used to synthesize the new γ-glutamyl compounds by using γ-glutamyl compounds as acyl donor substrate and transfering their γ-glutamyl moieties to acceptor substrate. However the GGT has the defect of having low thermal stability. In order to improve its poor thermal stability, the method of adding Ca2+ was adopted in this study, and the effects of added Ca2+ on the activity and thermal stability of GGT obtained from the fermentation of Bacillus subtilis were investigated. It was found that the thermal stability of GGT is greatly improved after it was treated with CaCl2 of 4 mmol·L-1at 37℃ for 30 min. As the GGT working temperature increases, the effect of Ca2+ treatment on increasing the thermal stability of GGT is more obvious. The kinetic constants of acylation reaction using GGT treated with Ca2+ were determined as Km= 0.23 mmol·L-1, Vmax= 0.015 mmol·L-Lmin-1 and the activation energy Ea =10.50 kJ·mol-1.The above Km and Ea values are significantly lower than those of acylation reaction using GGT without treated with Ca2+. The inactivation energy Ed of inactivation reaction for GGT was also calculated and it was found to be 60.47 kJ·mol-1, which is much higher than that of the GGT without treated with Ca2+ (50.42 kJ·mol-1). The study comes to the conclusion that the activity and thermal stability of GGT are obviously improved after treating it with Ca2+, and the Ca2+ could reduce the deactivation of GGT.关键词
γ-谷氨酰转肽酶/热稳定性/Ca2+/反应动力学/活化能Key words
γ-glutamyltranspeptidase/ thermal stability/ Ca2+/ kinetics/ activation energy分类
生物科学引用本文复制引用
宋希文,肖彦羚,周治,姚忠,徐虹,韦萍..Ca2+对枯草芽孢杆菌γ-谷氨酰转肽酶活性和热稳定性的影响[J].高校化学工程学报,2011,25(1):85-90,6.基金项目
国家973项目(2009CB724706) （2009CB724706）
国家科技支撑计划(2008BAI63B07) （2008BAI63B07）
江苏省高校自然科学研究重大项目(10KJA530014). （10KJA530014）
