Investigations on the interactions of DiAmsar with serum albumins: Insights from spectroscopic and molecular docking...

Diamine-sarcophagine (DiAmsar) binding to human serum albumin (HSA) and bovine serum albumin (BSA) was investigated under simulative physiological conditions. Fluorescence spectra in combination with Fourier transform infrared (FT-IR), UV-visible (UV-vis) spectroscopy, cyclic voltammetry (CV), and molecular docking method were used in the present work. Experimental results revealed that DiAmsar had an ability to quench the HSA and BSA intrinsic fluorescence through a static quenching mechanism. The Stern-Volmer quenching rate constant (Ksv ) was calculated as 0.372 × 10(3)  M(-1) and 0.640 × 10(3)  M(-1) for HSA and BSA, respectively. Moreover, binding constants (Ka ), number of binding sites (n) at different temperatures, binding distance (r), and thermodynamic parameters (∆H°, ∆S°, and ∆G°) between DiAmsar and HSA (or BSA) were calculated. DiAmsar exhibited good binding propensity to HSA and BSA with relatively high binding constant values. The positive ∆H° and ∆S° values indicated that the hydrophobic interaction is main force in the binding of the DiAmsar to HSA (or BSA). Furthermore, molecular docking results revealed the possible binding site and the microenvironment around the bond.