不同宿主来源的α-环糊精葡萄糖基转移酶分离纯化及化学修饰提高其热稳定性  

Purification of α-Cyclodextrin Glycosyltransferase and Study of Thermal Stability Improvement by Chemical Modification

作　　者：吴丹[1] 郑贤良[1] 吴敬[1] 

机构地区：[1]食品科学与技术国家重点实验室,江南大学,江苏无锡214122

出　　处：《食品与生物技术学报》2013年第3期287-292,共6页Journal of Food Science and Biotechnology

基　　金：中央高校基本科研业务费专项资金(JUSRP20917);食品科学与技术国家重点实验室科研基金(SKLF-MB-200802)资助

摘　　要：研究了不同宿主来源的α-环糊精葡萄糖基转移酶(α-CGT)经化学修饰后的热稳定变化,首先通过阴离子交换和疏水色谱分离纯化了来源于Paenibacillus macerans的天然α-CGT酶以及来源于Escherichia coli和Bacillus subtilis的重组α-CGT酶,再将α-CGT酶置于50℃水浴30min测残酶活,发现α-CGT酶残酶活分别为28%,30%和25%。首次采用戊二醛交联的方法研究了化学修饰对提高重组α-CGT酶稳定性的影响,E.coli重组表达的α-CGT酶经戊二醛交联成大分子聚合物后,与对照相比50℃水浴30 min后酶的热稳定性明显提高,水浴后仍有78%的酶活,酶活保有率相对未交联的酶提高了2.9倍。The -cyclodextrin glycosyltransferase （α-CGTase） from Paenibacillus macerans, Escherichia coli,Bacillus subtilis were purified respectively through a combination of ion-exchange and hydrophobic interaction chromatography. Specific activities of the CGTase from these three sources were 201 U/mg,200 U/rag and 199 U/rag,respectively. Chemical modification was further pertbrmed to improve the thermal stability of α-CGTase. The α-CGTase expressed in E. coli was cross-linked into a stable macromoleculs by glutarahlehyde. After water bathed at 50℃ for 30 min the stability of α-CGTase was improved as the cross-linked α-CGTase exhibit 78% left enzyme activity,which was 3.9 folds higher than that of dissociated α-CGTase.

关 键 词：酪蛋白 螯合铁 大鼠 补铁 效应 

分 类 号：Q814.1[生物学—生物工程]