title: Spectroscopic studies on the binding of bromocresol purple to different serum albumins and its bilirubin displacing action.
abstract: The interaction between bromocresol purple (BCP) and bovine serum albumin (BSA)/porcine serum albumin (PSA) was investigated both in the absence and presence of bilirubin (BR) using absorption/absorption difference spectroscopy. A significant red shift in the absorption maxima of BCP accompanied by a decrease in absorbance was indicative of BCP binding to albumin. The titration of BSA and PSA with BCP using absorption difference spectroscopy and analysis of results by Benesi-Hildebrand equation yielded the values of association constant, K as 9.9+/-0.9x10(4)Lmol(-1) and 4.1+/-0.3x10(4)Lmol(-1) for BSA and PSA, respectively. The differential extinction coefficient (Deltaepsilon) of 34,484M(-1)cm(-1) at 615nm and 41,870M(-1)cm(-1) at 619nm were estimated for BSA and PSA, respectively. Decrease in (DeltaAbs.)(615nm) of BCP-BSA complex with the increase in ionic strength suggested the role of hydrophobic interactions in the binding phenomenon. A significant blue shift in the absorption maxima and change in (DeltaAbs)(lambdamax) values of BR-albumin complexes upon addition of increasing concentrations of BCP revealed the BR displacing action of BCP on albumin molecule.
authors.affiliation: Biomolecular Research Group, Biochemistry Program, Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Faizah Mohd
authors.initials: FM
authors.lastname: Faizul
authors.forename: Habsah
authors.initials: H
authors.lastname: Abdul Kadir
authors.forename: Saad
authors.initials: S
authors.lastname: Tayyab
mesh_terms: D000818:Animals; D001663:Bilirubin / Q000737:chemistry*; D001962:Bromcresol Purple / Q000737:chemistry*; D002417:Cattle; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry*; D013053:Spectrophotometry; D013552:Swine
chemical_list: D012709:Serum Albumin; D001962:Bromcresol Purple; D001663:Bilirubin