Distribution and Transition of Native and Completely Unfolded Conformations in the Unfolding of Bovine Heart Cytochrome c Induced by Urea and Guanidine Hydrochloride  

作　　者：Yang, Jianting Zhang, Tan Lu, Cuizhu Bian, Liujiao 

机构地区：[1]College of Life Science, Northwest University, Xi＇an, Shaanxi 710069, China [2]Weapon Industry 521 Hospital, Xi＇an, Shaanxi 710065, China

出　　处：《Chinese Journal of Chemistry》2011年第9期1939-1946,共8页中国化学（英文版）

基　　金：Project supported by the National Natural Science Foundation of China （No. 21075097）.

摘　　要：The unfolding of bovine heart cytochrome c induced by urea and guanidine hydrochloride was first studied through intrinsic fluorescence emission spectra and fluorescence phase diagram and the results showed that both of them separately followed a two-state model. As the simplest sample of the unfolding of protein molecules induced by denaturants, an equation was presented to show the effect of the denaturant concentrations in denaturation solu- tion on the residual activity ratios of bovine heart cytochrome c in their two-state unfolding. There are two charac- teristic unfolding parameters K and m in this equation. The former is the thermodynamic equilibrium constant of the unfolding of bovine heart cytochrome c induced by denaturants, the latter is the number of denaturant molecules associated with a bovine heart cytochrome c molecule during the unfolding procedure, and through them the distri- bution and transition of native and completely unfolded bovine heart cytochrome c conformations under different concentrations of urea or guanidine hydrochloride in denaturation solution can be accurately described.The unfolding of bovine heart cytochrome c induced by urea and guanidine hydrochloride was first studied through intrinsic fluorescence emission spectra and fluorescence phase diagram and the results showed that both of them separately followed a two-state model. As the simplest sample of the unfolding of protein molecules induced by denaturants, an equation was presented to show the effect of the denaturant concentrations in denaturation solu- tion on the residual activity ratios of bovine heart cytochrome c in their two-state unfolding. There are two charac- teristic unfolding parameters K and m in this equation. The former is the thermodynamic equilibrium constant of the unfolding of bovine heart cytochrome c induced by denaturants, the latter is the number of denaturant molecules associated with a bovine heart cytochrome c molecule during the unfolding procedure, and through them the distri- bution and transition of native and completely unfolded bovine heart cytochrome c conformations under different concentrations of urea or guanidine hydrochloride in denaturation solution can be accurately described.

关 键 词：bovine heart cytochrome c UNFOLDING distribution and transition fluorescence spectroscopy biologi-cal activity 

分 类 号：Q559.9[生物学—生物化学] O611.63[理学—无机化学]