Magnetic
Polymeric Beads Functionalized with Different
Mixed-Mode Ligands for Reversible Immobilization of Trypsin
- Publication date
- Publisher
Abstract
In
this study, we describe a preparation of magnetic affinity support
carrying different ligands for immobilization of trypsin via adsorption.
The magnetic support was synthesized in the bead form using glycidylmethacrylate
(GMA) and methylmethacrylate (MMA) monomers. Three different ligands
(i.e., <i>p</i>-aminobenzoic acid, l-phenylalanine
and <i>p</i>-aminobenzamidine,) were attached on the aminated
magnetic beads surface via glutaraldhyde coupling. Specific surface
area of the mp(GMA/MMA) beads was found to be 21.4 m<sup>2</sup>/g.
The maximum trypsin adsorption was observed at pH 7.0 for <i>p</i>-aminobenzoic acid and l-phenylalanine and at
pH 8.0 for <i>p</i>-aminobenzamidine carrying ligand. The
maximum amounts of the enzyme adsorbed on the <i>p</i>-aminobenzoic
acid-, l-phenylalanine-, and <i>p</i>-aminobenzamidine-attached
magnetic beads reached 99.6, 84.2, and 75.9 mg/g with an enzyme activity
recovery of 69.4, 73.2, and 22.9%, respectively. The l-phenylalanine
ligand-attached support displayed a higher activity recovery than
those of the <i>p</i>-aminobenzoic acid- and the <i>p</i>-aminobenzamidine-attached magnetic beads. This carrier
showed also very good storage and operational stability. Trypsin immobilized
on <i>p</i>-aminobenzoic acid showed significant activity
toward casein. Trypsin could be repeatedly adsorbed and desorbed with
all of the ligand-attached beads without a noticeable loss in the
adsorption capacity