Temperature-induced conformational transition of bovine serum albumin in neutral aqueous solution by reversed-phase liquid chromatography

The temperature-induced conformational transition of bovine serum albumin (BSA) in neutral aqueous solution was studied using intrinsic fluorescence emission spectrum, reversed-phase liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the conformation transition thermodynamic parameters were determined in the temperature range 12-50 °C. The results showed that, in the temperature range 12-20 °C, BSA only existed in a single conformation state A, while in the temperature range 22-50 °C, it existed in two different conformation states: A and B. The percentage of conformation state A decreased while that of conformation state B increased with the increase in temperatures, and when temperature approached 50 °C conformation state B accounted for approximately 25% of all conformation states of BSA. In the conformational transition of BSA from conformation state A to conformation state B, the positive enthalpy change, entropy change and free energy changes demonstrated that the conformational transition was endothermic, nonspontaneous and mainly entropy-driven.