Partially folded conformations in the folding pathway of bovine carbonic anhydrase II: A fluorescence spectroscopic analysis

GdmCl-, urea-, and pH-induced unfolding pathways of bovine carbonic anhydra se II have been analyzed by using changes induced by different denaturing a gents in intensity anisotropy, life time, and parameter A value of intrinsi c fluorescence as well as intensity and life time of ANS (ammonium salt of 8-anilinonaphthalene-1-sulfonic acid) fluorescence. The formation of severa l stable unfolding intermediates, some of which were not observed previousl y has been established, This was further confirmed by representation of flu orescence data in terms of a "phase diagram", that is, I-lambda1 versus I-l ambda2 dependence, where I-lambda1 and I-lambda2 are the fluorescence inten sity values measured at wavelengths lambda (1) and lambda (2), respectively .