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In the present study, the biological activities of a new synthesized Pt(II)-complex, 2,2′ bipyridinphenyl isopentylglycin Pt(II) nitrate was investigated via its interaction with the most important blood carrier protein of human serum albumin (HSA), using fluorescence and Far-UV circular dichroism (CD) spectroscopic techniques and also molecular docking. Moreover, cytotoxicity activity of the complex was studied against breast cancer cell line of MDA MB231 using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The Pt(II)-complex has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching mechanism. According fluorescence quenching data, the binding parameters of the interaction were calculated and showed that hydrophobic interaction has an important role. The molecular docking results in coherent with fluorescence measurements illustrated that Pt(II) complex can bind to HSA at one position that located in the hydrophobic cavity of groove between drug site I and II. Also, experimental data on driving force in binding site was confirmed whereas theoretical results demonstrated Pt(II) complexinteract to HSA by hydrophobic interaction. Far-UV-CD results showed that Pt(II)-complex induced an increasing in the content of α-helical structure of the protein and stabilized it. Also, MTT assay represented growth inhibitory effect of the complex toward the breast cancer cell line. [ABSTRACT FROM AUTHOR]

The interaction of 1, 10-phenanthroline octhyldithiocarbamato palladium(II) nitrate ([Pd(Oct-dtc)(phen)]NO3) with human serum albumin (HSA) has been investigated by various spectroscopic techniques under physiological conditions. Here, HSA was titrated with the Pd(II) complex, followed by UV–Vis absorption spectroscopy to estimate a binding constant (Kb) and other thermodynamic parameters. The results indicate that the Pd (II) complex has a high affinity for bind HSA. Thermodynamic analysis showed that the enthalpy (ΔH°) and entropy changes (ΔS°) are positive and Gibbs free energy change (ΔG°) is negative which indicated that hydrophobic interactions played the predominant role in the binding process. Fluorescence spectroscopy were used to show the mechanism and binding parameters of this interaction. Utilizing the Stern–Volmer equation, the Pd(II) complex quenched the intrinsic fluorescence of HSA via a static quenching procedure. The specific binding distances between the tryptophan (donor) proteins and Pd(II) complex (acceptor) were estimated by Forster resonance energy transfer. The CD results also showed the conformational changes on serum albumin upon binding with the Pd(II) complex. [ABSTRACT FROM PUBLISHER]