中南大学学报（自然科学版）2013，Vol.44Issue(6)：2207-2213,7.
双金属Hg2+和Cu2+对木瓜蛋白酶活性与构象的影响
Effect of bimetal Hg2+ and Cu2+on activity and conformation of papain
摘要
Abstract
The effect of the bimetal Hg2+ and Cu2+ on activity and conformation of papain was studied.The secondary structures of the papain treated by the bimetal ions were investigated by characterization using FT-IR,fluorescence emitting and ultraviolet-absorption spectra.The results show that there exists the dosage-response relationship between the metals and papain activity,which indicates that the bimetal ions have Hormesis effect on the activity known as “a low dose stimulation,high dose inhibition”.Under low concentration,the bimetal ions exhibit synergistic activation effect on papain activity,and Cu2+ shields Hg2+ inhibition on the activity at high concentration.On the one hand,when the concentrations of Hg2+ and Cu2+ are 10-6 and 10-8 mol/L respectively,the strongest activity effect of the bimetal ions on papain is obtained.The content of the nonrandom secondary structures (α-helix and β-sheet) of the treated papain is the highest with the secondary structures of papain being most stable,and enzymatic affinity strongest and papain activity being best.When the concentrations of Hg2+ and Cu2+ are 10-4mol/L,the ordered structure content and papain activity are the lowest.The bimetal ions unfold the enzymic protein and cause the destruction of the secondary structures.The order degree ofpapain conformation is correlated positively with the activity.关键词
木瓜蛋白酶/双金属离子/构象/酶活性Key words
papain/ bimetal ions/ conformation/ activity分类
生物科学引用本文复制引用
张存滢,曾虹燕,熊龙斌,刘学英,Gohi A,蔡西玲,陈泽新..双金属Hg2+和Cu2+对木瓜蛋白酶活性与构象的影响[J].中南大学学报（自然科学版）,2013,44(6):2207-2213,7.基金项目
湖南省科技厅社会发展支撑计划(2011SK3138) （2011SK3138）
湖南省研究生科研创新项目(CX2011B265) （CX2011B265）
