Study on the thermodynamic characteristics between fluoroquinolone and bovine serum albumin

The binding reactions of the fluoroquinolone with bovine serum albumin (BSA) were investigated by microcalorimetry. The thermodynamic parameters were measured with the help of spectroscopy in a Tris–HCl buffer solution (pH 7.0, made isotonic with sodium chloride) at T = 298 K. Microcalorimetric measurements show that the molar change of enthalpy ΔrHm is insignificant for the reaction, which may suggest that the interaction is governed mainly by entropy, and the interaction between the protein and the drugs is stronger. The results also reveal an entropy–enthalpy compensation relationship of the interaction.