title: Bromophenol blue binding as a probe to study urea and guanidine hydrochloride denaturation of bovine serum albumin.
abstract: Urea and guanidine hydrochloride (GdnHCl) denaturation of bovine serum albumin (BSA) were investigated using bromophenol blue (BPB) binding as a probe. Addition of BPB to BSA produced an absorption difference spectrum in the wavelength range, 525-675 nm with a minimum at 587 nm and a maximum at 619 nm. The magnitude of absorption difference (DeltaAbs.) at 619 nm decreased on increasing urea/GdnHCl concentration and followed the denaturation curve. The denaturation was found to be a two-state, single-step transition. The transitions started at 1.75 and 0.875 M and completed at 6.5 and 3.25 M with the mid point occurring around 4.0 and 1.5 M urea and GdnHCl concentrations, respectively. The value of free energy of stabilization, DeltaGDH2O as determined from urea and GdnHCl denaturation curves was found to be 4041 and 4602 cal/mol, respectively. Taken together, these results suggest that BPB binding can be used as a probe to study urea and GdnHCl denaturation of BSA.
authors.affiliation: Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Adyani Azizah Abd
authors.initials: AA
authors.lastname: Halim
authors.forename: Habsah Abdul
authors.initials: HA
authors.lastname: Kadir
authors.forename: Saad
authors.initials: S
authors.lastname: Tayyab
mesh_terms: D000818:Animals; D001978:Bromphenol Blue; D002417:Cattle; D019791:Guanidine; D007202:Indicators and Reagents; D011489:Protein Denaturation; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013053:Spectrophotometry; D014508:Urea
chemical_list: D007202:Indicators and Reagents; D001978:Bromphenol Blue; D012710:Serum Albumin, Bovine; D014508:Urea; D019791:Guanidine