蛋白质在离子交换色谱上选择性和非吸附特性

对蛋白质在离子交换柱上选择民性和非吸附特性进行了研究。蛋白质在有机磷酸锆阳离子色谱柱上，其保留作用随流动相ｐＨ值在离子强度的增加而减小；蛋白质在强阳离子和强阴离子色谱柱上的保留作用，即是流动相中的ｐＨ值等于蛋白质的等当点，其净电荷为零。不册蛋白质仍有不同程度的保留，这主要是由于蛋白质的三维结构使电荷 密度的大小和分布的不均匀以及离子交换填料表面性质的影响。

Characteristics of Selective and Nonadsorptive of Proteins on Ion Exchange Chromatography

The characteristics of selective nonadsorptive of proteins on Ion Exchange Chromatography were described. (1) The retention of proteins on the organo zirconium phosphate column increases with the pI of the protein and decreases with increasing mobile phase pH and ionic strength(fig. 1). Rnase is more strongly retained at lower pH(fig. 2). (2) The retention maps of proteins(Fig. 3). Indicate that greatest retention on cation exchange column occurs when pH below the isoelectric point (pI), where the protein has a net positive charge whereas the largest retention on anion exchange column accurs pH above the isoelectric point where protein are negatively charge. For example, OVA with a pI of 4.6 would be retained on cation exchange column below pH 4.6 and on an anion exchange column above pH 4.6. (3) Chromatographic retention is plotted as a function of pH on both anion and cation exchange column(Fig. 3). OVA, Myo and Cytc can be retained anion exchange column even when pI=pH. The net charge retention model suggests that proteins showed not be retained on ion exchange column at their pI. This is not the case with many proteins. This behavior relates with charge distribution, charge density and their dimensional structure of proteins and matrix effects etc.