蛋白变性剂对多聚半乳糖醛酸酶及其化学修饰酶催化活性的影响  

Effects of Protein Denaturants on the Activities of Polygalacturonase and Chemically Modified Polygalacturonase

作　　者：刘小林[1,2] 伍志权[2] 黄磊[3] 黄卓烈[2] 黎春怡[2] 

机构地区：[1]宜春学院生命科学学院,江西宜春336000 [2]华南农业大学生命科学学院,广东广州510642 [3]江西宜春中学,江西宜春336000

出　　处：《高校化学工程学报》2012年第6期1009-1013,共5页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金项目(10074016)资助

摘　　要：为了探索几种蛋白质变性剂对多聚半乳糖醛酸酶的作用效果,以水溶性低分子量壳寡糖(COS,分子量约5000)作为修饰剂对已纯化的多聚半乳糖醛酸酶(PG)进行化学修饰,得到纯化的化学修饰酶(COS-PG),然后,测定不同蛋白变性剂(尿素、盐酸胍、SDS和苯酚)对纯化的PG和COS-PG催化活性的影响。结果表明,修饰后COS-PG的比活性是340.10 U(mg protein)1,比修饰前的PG提高了153%,COS-PG的糖含量比PG提高了43.11%,COS-PG的氨基修饰率为32.85%。SDS(十二烷基硫酸钠)、苯酚对PG和COS-PG活性有抑制作用,1 mmol L 1的SDS分别抑制了PG和COS-PG活性的80.99%和91.14%。10 mmol L 1的苯酚分别抑制了PG和COS-PG活性的34.08%和32.70%。低浓度的尿素和盐酸胍对PG有激活作用,5 mmol L 1的尿素使PG活性提高157.79%,3 mmol L 1的尿素使COS-PG的活性提高67.32%。2 mmol L 1的盐酸胍使PG活性提高57.64%,1 mmol L 1的盐酸胍使COS-PG的活性提高5.76%。In order to investigate the effects of several protein denaturants on the activity of polygalacturonase and modified polygalacturonase, the low molecular chitosan （COS, MW about 5000） was used to modify the purified polygalacturonase （PG） to get chemically modified polygalacturonase （COS-PG） and four denaturants （urea, guanidine hydrochloride, sodium dodecyl sulphate, phenol） were used separately for the measurement of their influences on the catalytic activites of PG and COS-PG. It was found that, after modification, the activity of COS-PG is 340.10 U.（mg protein）-1, which is 153% higher than that of PG, and the polycarbohydrate content in COS-PG is 43.11% higher than that of PG. The amino modification ratio of COS-PG is 32.85%. Sodium dodecyl sulphate （SDS） and phenol can inhibite the activities of PG and COS-PG. SDS of 1 mmol.L-1inhibites the activities of PG and COS-PG by 80.99% and 91.14%, respectively, and 10 mmol.L-1 phenol inhibites the activities of PG and COS-PG by 34.08% and 32.70%, respectively. Urea and guanidine hydrochloride in low concentrations can activate PG and COS-PG. Urea of 5 mmol.L-1increases the activity of PG by 157.79%, and urea of 3 mmol.L-1 increases the activity of COS-PG by 67.32%. Guanidine hydrochloride of 2 mmol.L-1 increases the activity of PG by 57.64%, and guanidine hydrochloride of 1 mmol.L-1 increases the activity of COS-PG by 5.76%.

关 键 词：多聚半乳糖醛酸酶(PG) 蛋白变性剂 壳寡糖(COS) 化学修饰 

分 类 号：Q557.9[生物学—生物化学] Q936