Binding interaction between serum albumins and perylene-3,4,9,10-tetracarboxylate – A spectroscopic investigation

A comprehensive understanding of the transportation of perylene-3,4,9,10-tetracarboxylate (PTCA) derivatives in blood will be beneficial for the investigations in drug design and toxicology. Hence we hereby investigated the binding interaction of perylene-3,4,9,10-tetracarboxylate tetrapotassium salt (PTK) with serum albumin in physiological buffer solution (pH 7.4) at 298 K by fluorescence spectra, synchronous fluorescence spectra, and Circular Dichroism (CD) techniques. It was proved that PTK quenched the intrinsic fluorescence of Serum albumins by forming a complex between them which is confirmed from the fluorescence lifetime studies. The binding constant (K) were calculated using the modified Stern–Volmer equation which indicates that affinity of HSA is more than that of BSA towards PTK. Using Forster Resonance Energy Transfer theory, the distance (r0) between Serum Albumins and PTK was calculated. In addition, the results obtained from the synchronous fluorescence and CD spectra suggested the change in the microenvironment and conformation of Serum Albumin during the binding reaction.

Graphical abstractThis paper investigates the binding interaction of perylene-3,4,9,10-tetracarboxylate tetrapotassium salt (PTK) with serum albumins (HSA and BSA) in physiological buffer solution (pH 7.4) at 298 K using the fluorescence spectroscopic and circular dichroism techniques.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The quenching studies suggest that the non-radioactive energy transfer occurs in the interaction. ► Lifetime studies confirmed the mechanism of binding as static (complex formation). ► CD spectra showed the change in molecular conformation of Serum Albumin in the presence of PTK. ► This interaction could be a useful guideline for further investigations in drug design and toxicology.