Studies on Interaction between 4‐(4‐Hydroxybut‐2‐ynyloxy)‐3‐(phenylsulfonyl)‐1,2,5‐oxadiazole‐2‐oxide and Bovine Serum Albumin by Spectroscopic Method

The interaction between 4-(4-hydroxybut-2-ynyloxy)-3-(phenylsulfonyl)-1,2,5-oxadiazole-2-oxide (FB) and bovine serum albumin (BSA) was studied by spectroscopic methods including fluorescence and UV-Vis absorption spectroscopy. The quenching mechanism of fluorescence of BSA by FB was considered to be a dynamic quenching procedure. The number of binding sites n and apparent binding constant K were measured by fluorescence quenching method. The results indicate that there is FB molecular binding with BSA, and forming 1:1 complex. The thermodynamic parameters such as ΔH, ΔG and ΔS, etc., were calculated. The results indicate that the binding reaction is mainly entropy-driven and hydrophobic forces play major role in the binding reaction. The distance r between donor (BSA) and acceptor (FB) was obtained according to Forster theory of non-radioactive energy transfer.