β-半乳糖苷酶交联酶聚体的制备及酶学性质研究  

Preparation and properties of cross- linked enzyme aggregates( CLEAs) of β-galactosidase from Kluyveromyces lactis

作　　者：邢肖肖[1] 王梦凡[1] 齐崴[1] 苏荣欣[1] 何志敏[1] 

机构地区：[1]天津大学化工学院化学工程研究所,天津300072

出　　处：《食品工业科技》2014年第23期158-162,167,共6页Science and Technology of Food Industry

基　　金：国家自然科学基金(21206113;20976125)

摘　　要：研究了乳酸克鲁维酵母所产β-半乳糖苷酶交联酶聚体(CLEAs)的制备条件和酶学性质,并应用于乳糖为底物催化制备低聚半乳糖(GOS)的反应体系中。结果表明:将β-半乳糖苷酶酶液稀释20倍,按体积比1∶1加入异丙醇,4℃下沉淀30min,加入体积分数为0.125%交联剂戊二醛,4℃下交联30min,离心洗涤,所得CLEAs的酶活保留达45.77%;与游离酶相比,β-半乳糖苷酶CLEAs的最适p H由7提高至8,最适温度由30℃提高至37℃,p H和温度的适用范围有所拓宽,且37℃下热稳定性提高1倍,具有更高的转糖苷活性选择性,适于制备功能性低聚半乳糖。The preparation and properties of cross- linked enzyme aggregates （CLEAs） of β- galactosidase from Kluyveromyces lactis were investigated.Furthermore, the β-galactosidase CLEAs was applied to the preparation of galactooligosaccharides （GOS）using lactose as the substrate. The optimal conditions for preparation of β-galactosidase CLEAs were determined as 20 times dilution of original enzyme liquid, 1：1 of 2-propanol （v/v） precipitation for 30rain at 4℃, and cross-linking of 30min by 0.125% （v/v） glutaraldehyde. Thus 4.5.77% of the reservation activity could be obtained.Compared with the free enzyme,the optimal pH of β-galactosidase CLEAs increased from 7 to 8, and the optimal temperature of β- galactosidase CLEAs increased from 30℃ to 37℃. Therefore,the CLEAs had wider range of pH and temperature.Meanwhile, the thermal stability of CLEAs was two times of free enzyme＇ s.ln addition, the selectivity of β- galactosidase CLEAs for GOS synthesis was higher than that of free enzyme.which was more suitable for the Dreoaration of functional GOS.

关 键 词：乳酸克鲁维酵母 Β-半乳糖苷酶 交联酶聚体 低聚半乳糖 

分 类 号：TS201.3[轻工技术与工程—食品科学]