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Highly Sensitive and Quantitative Detection of Proteins and Their Isoforms by Capillary Isoelectric Focusing Method
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Ion-exchange chromatography of proteins near the isoelectric points

S Yamamoto1, T Ishihara

  • 1Department of Chemical Engineering, Yamaguchi University Tokiwadai, Ube, Japan. shu-yama@po.cc.yamaguchi-u.ac.jp

Journal of Chromatography. A
|September 10, 1999
PubMed

The retention and the resolution of beta-lactoglobulin A and B (LgA, LgB) were investigated with various ion-exchange chromatography media. The number of sites involved in the retention (adsorption) decreased as the mobile phase pH approached the isoelectric points pI (=5.1-5.2). However, even at pH 5.2 both LgA and LgB were retained on anion- and cation-exchange chromatography columns. The separation (resolution) of LgA and LgB became better when the pH approached the pI in anion-exchange chromatography columns where the number of adsorption site values are small (ca. 2-3). The two proteins were not separated on cation-exchange chromatography columns. Factors affecting the resolution and the retention near the pI were discussed.

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