A structural study on the interaction of the anti-cancer compound of Platinum complex with human serum albumin

Human serum albumin (HSA) is the most abundant protein in blood plasma, which is responsible for 80% of blood pressure; it also acts as a carrier protein for many compounds in the blood such as drugs. In the present study, the interaction and side-effects of a newly-designed anti-cancer compound of isopentyl-glycine1, 10-phenanthroline Platinum nitrate on HSA have been investigated. In this investigation, the side effects, values of the number of binding sites and the association binding constants of new synthesized Pt(II) complex have been studied by different spectroscopic (fluorescence and circular diachronic (CD) techniques at different temperatures of 25 and 37 °C. The analysis of fluorescence spectra showed that the addition of the complex led to a significant reduction in the fluorescence spectra of HSA via quenching mechanism. Also, it can change the three-dimensional structure of tryptophan existing in the protein. The number of binding sites, the Stern-Volmer quenching constant and the association constant of the complex were calculated on the HSA protein. The analysis of circular dichroic spectra showed that the complex can change the regular secondary structure of the protein via reduction of α helical structure and increase of β sheet structure which indicates a decrease in the stability of the protein. According to the results obtained, it can be concluded that this new synthesized Pt(II) complex can bind to the main blood carrier protein (HSA) and change the secondary and tertiary structure of the protein which can be considered as the side-effects of this drug.