A DSC study of zinc binding to bovine serum albumin (BSA)

Abstract

The thermal denaturation of bovine serum albumin (BSA) is a kinetically and thermodynamically controlled process. The effects of zinc binding to bovine serum albumin (BSA), followed by differential scanning calorimetry (DSC), were investigated in this work, with the purpose of obtaining a better understanding of the albumin/zinc interaction. From the DSC curves, the thermodynamic parameters of protein denaturation were obtained, i.e., the temperature of thermal transition maximum (T m), calorimetric enthalpy (?Hcal), van't Hoff enthalpy (?HvH), the number of binding sites (I, II), the binding constants for each binding site (K bI, K bII) and the average number of ligands bound per mole of native protein X N. The thermodynamic data of protein unfolding showed that zinc binding to bovine serum albumin increases the stability of the protein (higher values of ?Hcal) and the different ratio ?Hcal/?HvH indicates the perturbation of the protein during thermal denaturation.