The unfolding intermediate state of calf intestinal alkaline phosphatase during denaturation in guanidine solutions.
The equilibrium unfolding of calf intestinal alkaline phosphatase in guanidinium chloride (GdmCl) solutions was studied by following the fluorescence and ultraviolet difference spectra. At low concentrations of GdmCl (< 1.6 M), the fluorescence intensity decreased with a slight red shift of the emission maximum from 332 nm to 344 nm. An unfolding intermediate state was observed at a broad concentration range of GdmCl as a denaturant (between 1.6 and 2.6 M). This intermediate was characterized by increased fluorescence emission intensity, ultraviolet difference absorption at 236 nm and 260 nm, as well as increased binding to the protein and red shift of the fluorescence probe 1-anilinonaphthalene-8-sulfonic acid.
Zhang
Ying-Xia
YX
Department of Chemistry, Capital University of Medical Sciences, Beijing 100054, PR China. yingxia@sohu.com
Song
Xiao-Hong
XH
Yan
Shu-lian
SL
Zhou
Hai-Meng
HM
D000469:Alkaline Phosphatase / Q000737:chemistry* / Q000378:metabolism*; D000817:Anilino Naphthalenesulfonates; D000818:Animals; D002417:Cattle; D019791:Guanidine / Q000494:pharmacology*; D007422:Intestines / Q000201:enzymology*; D011487:Protein Conformation / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
D000817:Anilino Naphthalenesulfonates; C027132:1-anilino-8-naphthalenesulfonate; D000469:Alkaline Phosphatase; D019791:Guanidine