title: Affinity of two novel five-coordinated anticancer Pt(II) complexes to human and bovine serum albumins: a spectroscopic approach.
abstract: The interactions of two organoplatinum complexes, [Pt(C^N)Cl(dppa)], 1, and [Pt(C^N)Cl(dppm)], 2 (C^N = N(1), C(2')-chelated, deprotonated 2-phenylpyridine, dppa = bis(diphenylphosphino)amine, dppm = bis(diphenylphosphino)methane), as antitumor agents, with bovine serum albumin (BSA) and human serum albumin (HSA) have been studied by fluorescence and UV-vis absorption spectroscopic techniques at pH 7.40. The quenching constants and binding parameters (binding constants and number of binding sites) were determined by fluorescence quenching method. The obtained results revealed that there is a strong binding interaction between the ligands and proteins. The calculated thermodynamic parameters (ΔG, ΔH, and ΔS) confirmed that the binding reaction is mainly entropy-driven, and hydrophobic forces played a major role in the reaction. The displacement experiment shows that these Pt complexes can bind to the subdomain IIA (site I) of albumin. Moreover, synchronous fluorescence spectroscopy studies revealed some changes in the local polarity around the tryptophan residues. Finally, the distance, r, between donor (serum albumin) and acceptor (Pt complexes) was obtained according to Förster theory of nonradiation energy transfer.
authors.affiliation: Department of Chemistry, Shiraz University, Shiraz, Iran.
authors.forename: Fayezeh
authors.initials: F
authors.lastname: Samari
authors.forename: Bahram
authors.initials: B
authors.lastname: Hemmateenejad
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Shamsipur
authors.forename: Mehdi
authors.initials: M
authors.lastname: Rashidi
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Samouei
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry*; D002417:Cattle; D006801:Humans; D010984:Platinum / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000970:Antineoplastic Agents; D012709:Serum Albumin; D010984:Platinum