The effect of structural alterations of three mammalian serum albumins on their binding properties

• Published in: Journal of molecular structure Vol. 1044; pp. 152 - 159
• Main Authors: Równicka-Zubik, J., Sułkowski, L., Maciążek-Jurczyk, M., Sułkowska, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 24.07.2013
• Subjects: Alterations; Binding; Binding ability; binding properties; binding sites; blood serum; cattle; Constants; Fluorescence; Fluorescence spectroscopy; Human; humans; Piroxicam; Quenching; Residues; Serum albumin; sheep; Fluorescence spectroscopy; Binding ability; Piroxicam; Serum albumin
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2012.12.049

The binding of piroxicam (PIR) to human (HSA), bovine (BSA) and sheep (SSA) serum albumin in native and destabilized/denaturated state was studied by the fluorescence quenching technique. Quenching of the intrinsic fluorescence of three analyzed serum albumins was observed due to selective exciting of tryptophanyl and tyrosil residues at 295nm and 280nm. Based on fluorescence emission spectra the quenching (KQ) and binding constants (Ka) were determined. The results showed that PIR is bound mainly in IIA subdomain of HSA and is additionally able to interact with tyrosil groups located in subdomains IB, IIB or IIIA. PIR interacts only with tryptophanyl residues of BSA and SSA [Trp-214, Trp-237 (IIA) and Trp-135, Trp-158 (IB)]. The presence of denaturating factors modified the mechanism of fluorescence quenching of SSA by PIR. Linear Scatchard plots suggest that HSA, BSA and SSA bind PIR in one class of binding sites.