A Recyclable Poly(ionic liquid)s Enzyme Reactor for Highly Efficient Protein Digestion

One of the most significant tasks for proteomic research and industrial applications, is the preparation of recyclable enzyme reactor. Herein, a novel recyclable enzyme reactor has been developed based on monodispersed spherical poly(quaternary ammonium ionic liquid)s particles immobilized trypsin. A new quaternary ammonium ionic liquids functional monomer was first synthesized. The ionic liquids functional monomer was then copolymerized with ethylene glycol dimethacrylate by precipitation polymerization. The resultant monodispersed spherical particle showed a large surface area (231 m2/g) and high binding capacity for trypsin (200 mg/g) due to the large surface area and strong interaction. The polymer microsphere loaded trypsin was used as an enzyme reactor for the digestion of standard protein, semi-complex samples and skim milk, respectively. The results indicated that the enzyme reactor exhibited highly efficient protein digestion and excellent stability. The digestion time of the present ionic liquids enzyme reactor for the digestion of protein, the solution could be reduced to even 5 min. The ionic liquids enzyme reactor showed excellent reusability and could be reused for more than four times. When it was kept at 4 °C for 12 d, and used for skim milk digestion, the obtained MALDI-TOF score could also reach 88 with 29 matched peptides.