title: The unfolding intermediate state of calf intestinal alkaline phosphatase during denaturation in guanidine solutions.
abstract: 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.
authors.affiliation: Department of Chemistry, Capital University of Medical Sciences, Beijing 100054, PR China. yingxia@sohu.com
authors.forename: Ying-Xia
authors.initials: YX
authors.lastname: Zhang
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Song
authors.forename: Shu-lian
authors.initials: SL
authors.lastname: Yan
authors.forename: Hai-Meng
authors.initials: HM
authors.lastname: Zhou
mesh_terms: 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
chemical_list: D000817:Anilino Naphthalenesulfonates; C027132:1-anilino-8-naphthalenesulfonate; D000469:Alkaline Phosphatase; D019791:Guanidine