STUDY OF THE INTERACTION BETWEEN XYLAZINE AND BOVINE SERUM-ALBUMIN BYFLUORESCENCE QUENCHING MEASUREMENTS

The binding of xylazine to bovine werum albumin (BSA) was studied by f luorescence quenching, as a function of temperature, The experimental data could be fitted to both the Stern-Volmer equation and the Stern-V olmer equation modified by Lehrer, The temperature dependence of the S tern-Volmer constant, K-SV suggests that the mechanism of the quenchin g process is mainly dynamic in origin, The thermodynamic parameters we re estimated based on such temperature dependence. The positive values found for the enthalpy and entropy changes seem to indicate that the hydrophobic contribution is the predominant intermolecular force stabi lizing the xylazine-BSA complex. These results, together with the spec tral changes in the fluorescence emission spectra of BSA induced by xy lazine, suggest that the interaction may take place in subdomains IIA and IIIA since these subdomains have been proposed to bind drugs and o ther hydrophobic materials.