Abstract: The thermostability of some proteins in weak cation-exchange chromatography was investigated at 20-80 ℃. The results show that there is a fixed thermal denaturation transition temperature for each protein. The appearance of the thermal transition temperature indicates that the conformations of the proteins are destroyed seriously. The thermal behavior of the proteins in weak cation-exchange and hydrophobic interaction chromatographies were compared in a wide temperature range. It was found that the proteins have a higher thermostability in a weak cation-exchange chromatography system. The thermodynamic parameters(ΔH⁰, ΔS⁰) of those proteins were determined by means of Van't Hoff relationship(lnk'-1/T). According to standard entropy change(ΔS⁰), the conformational change of the proteins was judged in the chromatographic process. The linear relationships between ΔH⁰ and ΔS⁰ can be used to evaluate "compensation temperature"(β) at the protein denaturation and identify the identity of the protein retention mechanism in weak cation-exchange chromatography.

Key words: Weak cation-exchange chromatography, Protein, Thermodynamic parameter, Conformational change