Immobilization of Chymotrypsin on Silica Beads Based on High Affinity and Specificity Aptamer and Its Applications

Aptamers with high affinity and specificity to targets, bring new approaches to immobilizing proteins or enzymes. In this work, a group of single-stranded DNA aptamers specific for chymotrypsin were obtained by SELEX method in vitro. After investigation and characterization of all aptamers, AptC.1 (abbreviation for the aptamer with the highest affinity for chymotrypsin) was selected and grafted onto silica matrix with the help of glutaraldehyde as linker, and used subsequently to immobilize chymotrypsin. Specifically, it is shown in experiment that, 12.65 μg of chymotrypsin could be immobilized on 10 mg of AptC.1-Silica in 10 mM pH 8.0 borate solutions, and the activity of immobilized enzyme was not inhibited. Bovine serum albumin, myoglobin and cytochrome c were introduced to investigate the enzymatic performance of prepared immobilized chymotrypsin reactor. All these results demonstrated that aptamer could serve as a potential medium for the immobilization of proteins or enzymes.