Cytotoxic and spectroscopic studies on binding of a new synthesized bipyridine ethyl dithiocarbamate Pt(II) nitrate complex to the milk carrier protein of BLG

In the present investigation, we have decided to study the interaction between the bovine whey carrier protein of β-lactoglobulin (BLG) with a newly synthesized Pt(II) complex (bipyridine ethyl dithiocarbamate Pt(II) nitrate), as an anti-cancer compound using fluorescence and circular dichroism (CD) spectroscopic methods at two different temperatures of 25 and 37 °C. Also, cytotoxicity and apoptotic activity of this complex have studied against cancer model cell line of K562. Results of intrinsic fluorescence of BLG represent that Pt(II) complex has strong ability to quench the intrinsic fluorescence of protein through dynamic quenching procedure. The values of binding constant (0.21 and 0.27 μM^?1 at 25 and 37 °C, respectively) and number of binding site calculated according to the quenching methods at different temperatures. Also, thermodynamic parameters data suggested that hydrophobic interaction plays a major role in the interaction of complex with BLG. In addition, far-UV-CD results show that Pt(II) complex did not induce any significant changes in the secondary structure of BLG. Cytotoxicity and apoptotic effects of the complex toward the cancer cell line of K562 were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and 4,6-diamidino-2-phenylindole staining methods. From above results, it can be concluded that the bovine whey carrier protein of BLG could bind to be a suitable transfer for this new anti-cancer compound and may be suggested that the anti-tumor activity of this complex reveals typical morphological features of apoptotic death.