N-糖基化对植酸酶phy(QF)酶学性质的影响  

The Effects of N-glycosylation on Enzymological Properties of Phytase Phy(Q_F)

作　　者：王茜[1] 宋玛丽[1] 杜军[1] 付月君[1] 胡风云[2] 梁爱华[1] 

机构地区：[1]山西大学生物技术研究所、化学生物学与分子工程教育部重点实验室,山西太原030006 [2]山西省人民医院神经内科,山西太原030012

出　　处：《华北农学报》2015年第1期177-181,共5页Acta Agriculturae Boreali-Sinica

基　　金：国家自然科学基金项目(31372199;31272100);国家高技术研究发展计划“863”计划项目(2012AA020809);山西省回国留学人员科研资助项目(2012-重点1)

摘　　要：为探讨N-糖基化对植酸酶phy(QF)酶学性质的影响,将植酸酶基因phy(QF)在毕赤酵母中进行了表达,利用脱糖基化酶Endo Hf去除重组植酸酶phy(QF)的糖链,对去除糖链前后的植酸酶phy(QF)进行了纯化和酶学性质研究与比较。结果表明,糖基化的植酸酶phy(QF)分子量约为53 k Da,酶活为3 201 U/mg,Km=392μmol/L,Vmax=3 267 U/mg;糖基化的植酸酶phy(QF)最适p H值为4.5,最适反应温度为55℃,与去糖基化的植酸酶phy(QF)的最适p H值无明显区别,比去糖基化的植酸酶phy(QF)最适温度提高了5℃,Tm值提高约2℃。经70℃孵育10 min后,去糖基化的植酸酶phy(QF)完全失活,而糖基化的植酸酶phy(QF)仍残留13%的活性,说明N-糖基化作为一种重要的翻译后修饰,对植酸酶phy(QF)的稳定性有促进作用。In order to study the effects of N-glycosylation on enzymological properties of phytase phy （QF）,the recombinant phytase gene phy（QF） was expressed in pichia pastoris GS115.Phytase phy（QF） was deglycosylated by endoglycosylase Endo H f .Enzymology properties of glycosylated phy （QF）and deglycosylated phy （QF）were an-alyzed.The results showed that the glycosylated phy （QF） had a specific activity of 3 201 U/mg with an MW of ap-proximately 53 kDa and the Km and Vmax of glycosylated phy（QF） were 392 μmol/L and 3 267 U/mg,respectively. The optimal pH value of glycosylated phy（QF） was 4.5 and was consistented with that of deglycosylated phy （QF）. However,the optimal temperature of glycosylated phy （QF） was 55 ℃,5 ℃ higher than that of deglycosylated phy （QF） and 2 ℃increased in the melting temperature （Tm）.The glycosylated phy（QF） exhibited 13%residual ac-tivity after treatment at 70 ℃for 10 min and deglycosylated phy （QF）was completely deactivated under the condi-tion.As one of posttranslational modifications ,N-glycosylation may play an important role in improving the stability of phytase phy （QF）.

关 键 词：植酸酶 N-糖基化 毕赤酵母 热稳定性 圆二色谱 

分 类 号：Q55[生物学—生物化学]