Unfolding of Bovine Heart Cytochrome c Induced by Urea and Guanidine Hydrochloride  

作　　者：边六交 张潭 杨晓燕 刘莉 郑晓晖 

机构地区：[1]College of Life Science, Northwest University, Xi'an, Shaanxi 710069, China

出　　处：《Chinese Journal of Chemistry》2011年第4期813-821,共9页中国化学（英文版）

基　　金：Project supported by the National Natural Science Foundation of China （No. 21075097）.Acknowledgements We would like to thank Ms. Cui-Zhu Lu for her scientific support and helpful discussion.

摘　　要：The unfolding of bovine heart cytochrome c induced by urea and guanidine hydrochloride was studied through their intrinsic fluorescence emission spectra, fluorescence phase diagrams, fluorescence quenching, size-exclusion chromatographies, native polyacrylamide gel electrophoreses and deactivation profiles. The results showed that during their unfolding in urea and guanidine hydrochloride solutions, bovine heart cytochrome c molecules existed only in a unimolecular form and their bi-molecular and/or poly-molecular aggregates and aggregate precipitates were not formed all along. When the urea and guanidine hydrochloride concentrations in denaturation solution were separately about 6.0 and 3.0 mol/L, they could be completely deactivated and almost all of the tryptophan residues originally embedded in the interior of their molecules were exposed to the surface of their molecules. Different from the unfolding of the most often used horse heart cytochrome c, that of bovine heart cytochrome c induced by urea and guanidine hydrochloride was separately a completely co-operative procedure and followed a two-state model.The unfolding of bovine heart cytochrome c induced by urea and guanidine hydrochloride was studied through their intrinsic fluorescence emission spectra, fluorescence phase diagrams, fluorescence quenching, size-exclusion chromatographies, native polyacrylamide gel electrophoreses and deactivation profiles. The results showed that during their unfolding in urea and guanidine hydrochloride solutions, bovine heart cytochrome c molecules existed only in a unimolecular form and their bi-molecular and/or poly-molecular aggregates and aggregate precipitates were not formed all along. When the urea and guanidine hydrochloride concentrations in denaturation solution were separately about 6.0 and 3.0 mol/L, they could be completely deactivated and almost all of the tryptophan residues originally embedded in the interior of their molecules were exposed to the surface of their molecules. Different from the unfolding of the most often used horse heart cytochrome c, that of bovine heart cytochrome c induced by urea and guanidine hydrochloride was separately a completely co-operative procedure and followed a two-state model.

关 键 词：bovine heart cytochrome c UNFOLDING DENATURANTS fluorescence spectroscopy ELECTROPHORESIS 

分 类 号：Q559.9[生物学—生物化学] O629.73[理学—有机化学]