Retention and enantioselectivity of 2-arylpropionic acid derivatives on an avidin-bonded silica column Influence of base materials, spacer type and protein modification

Abstract

The influences of pore sizes of base materials, spacer type and protein modification on the chiral resolution of 2-arylpropionic acid derivatives on avidin (AVD)-bonded silica materials were investigated. With regard to the pore sizes of the base silica materials, 120-Å materials gave higher enantioselectivity and resolution than 300-Å materials. With regard to spacer type, aminopropyl (AP)-silica gels activated by N,N′-disuccinimidyl carbonate (DSC) and N,N′-disuccinimidyl suberate (DSS) and glycerylpropyl (GP)-silica gels activated by 1,1'-carbonyldiimidazole (CDI) were compared. The AP-silica gels activated by DSC gave the highest protein coverage and resolution. Modified AVD-bonded materials were prepared by reaction with glutaraldehyde, glyceraldehyde and benzaldehyde. The retentive and enantioselective properties of 2-arylpropionic acid derivatives on these modified AVD columns were compared with those on an unmodified AVD column. The retentions of 2-arylpropionic acid derivatives on the modified AVD columns were shorter than those on the unmodified AVD column, whereas the modified AVD columns gave lower or approximately equal enantioselectivity compared with the unmodified AVD column. These results may be attributed to a decrease in the number of ion-exchange sites for retention and chiral recognition, and/or changes in protein conformation as a result of modification.