Aptamers are nucleic acid-based high affinity ligands that are able to capture their corresponding target
throughmolecular recognition.Inthis study, several DNAaptamers withhighaffinity andspecificity for -
glucuronidases (PGUS-E) were obtainedby ourmodifiedSELEXmethod.Among them,Apt5 andApt9 were
selected as representatives and covalently linked to magnetic beads, respectively. The aptamer-modified
magnetic beads were characterized and successfully applied to one-step purification and immobilization
of PGUS-E from the complex cell lysates. By conveniently adjusting the pH and ion strength, the PGUS-E
purities reached 84% for Apt5-modified beads and 88% for Apt9-modified beads. Moreover,the maximum
PGUS-E capturing capacity of the Apt5 and Apt9 modified magnetic beads were found to be 31.75 g/mg
and 32.95 g/mg, respectively. The immobilized PGUS-E on aptamer-based magnetic beads showed good
reusability, and the conversion of glycyrrhizin still remained more than 70% after 7 cycles. In addition,the
aptamer-modified beads support can be easily regenerated, and the conversion rate of glycyrrhizin (GL)
was still 62% after the 7th cycle of regeneration. This investigation can be easily extended to other enzyme
systems and may help open a generic route to develop a novel enzyme immobilization technology for
biocatalysis based on aptamer.