A study on the interaction between 3-spiro-piperidones and bovine serum albumin using spectroscopic approaches.

The interaction between 3-spiro-2'-pyrrolidine-3'-spiro-3″-piperidine-2,3″-dione (PPD) and bovine serum albumin (BSA) in aqueous solution was studied using fluorescence and UV-vis spectroscopy. Fluorescence emission data revealed that BSA (1.00 × 10(-5) mol/L) fluorescence was statically quenched by PPD at various concentrations, which implies that a PPD-BSA complex was formed. The binding constant (KA ), the number of binding sites (n) and the specific binding site of the PPD with BSA were determined. Energy-transfer efficiency parameters were determined and the mechanism of the interaction discussed. The thermodynamic parameters, ΔG, ΔH and ΔS, were obtained according to van't Hoff's equation, showing the involvement of hydrophobic forces in these interactions. The effect of PPD acting on the BSA conformation was detected by synchronous fluorescence.

Spectroscopic studies on the interaction of BSA and 5-spiro-3'-piperidine-2″-spiro-3″-indole-4',2″-diones.

The interaction of 5-spiro-3'-piperidine-2″-spiro-3″-indole-4',2″-diones (SPSDs), an anti-tumor drug, to bovine serum albumin (BSA) in aqueous solution has been investigated by fluorescence spectra and ultraviolet-visible (UV-vis) spectra at pH 7.40. We have studied the effect of four substituents on the SPSD for the first time. The results of fluorescence titration indicated that SPSD can quench the intrinsic fluorescence of BSA and the quenching mechanism has been analyzed. The binding sites number (n), the binding constant (K(A)) and the spatial-distance (r) of SPSD with BSA without or with substituents on the benzene ring at 302 and 310 K have been calculated. The results show that the presence of the substituents increased the binding constant and changed the binding distance between the acceptor and the donor, which possibly results from the formation of SPSD-BSA complex. We have investigated the possible sub-domain on BSA where bind SPSD by displacement experiments. The effect of SPSD on the conformation of BSA has also been analyzed using synchronous fluorescence under experimental conditions.

Spectroscopic analyses on interaction of Naphazoline hydrochloride with bovine serum albumin.

The fluorescence and ultraviolet spectroscopy were explored to study the interaction between Naphazoline hydrochloride (Naphcon) and bovine serum albumin (BSA) at three different temperatures (292, 301, and 310 K) under imitated physiological conditions. The quenching mechanism of BSA by Naphacon was interpreted using the Stern-Volmer mechanism, and a combined quenching (dynamic and static quenching). The binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. According to Förster non-radiation energy transfer theory, the binding distance between BSA and Naphcon was found to be 4.71 nm. Synchronous fluorescence spectroscopy showed the conformation of BSA changed in the presence of Naphacon. In addition, the effect of some common metal ions (Mg(2+), Ca(2+), Ni(2+), Cu(2+), and Fe(2+)) on the binding constant between Naphcon and BSA was examined.