Abstract

Imprinting of macromolecule such as proteins with molecular imprinting technique remains challenge because of their bulkiness, structural complexity and sensitivity of denaturation. The purpose of this study was to synthesize a Lys-MIP film on the surface of the MWNTs by surface molecular imprinting technique, and subsequently selectively recognized and purified Lys from egg white. The Lys-MIP film was prepared using AAm as functional monomer, MBA as cross-linker, APS and TEMED as initiator under the optimized conditions. The polymer was characterized by TEM, FT-IR, TGA, and BET, as well. The equilibrium adsorption experiments and dynamic adsorption experiments were carried out to determine the binding capacity and the equilibrium time. The results showed that adsorption capacity of the Lys-MIP film was 20.89 mg g-1 at 0.50 mg mL-1, and adsorption capacity was 15.37 mg g-1 for the NIP. 82.10% of binging was obtained within 30 min and the adsorption equilibrium was achieved within 300 min. The selectivity adsorption experiments showed the Lys-MIP film had higher affinity and capacity for Lys than that for the competitive proteins, such as Cyt C, Mb, Hb and BSA. The relative selectivity coefficients for Lys/Cyt C, Lys/Mb, Lys/Hb, and Lys/BSA were 1.30, 1.30, 3.12 and 2.82, respectively. Purification experiment of Lys from egg white showed that adsorption capacity of the Lys-MIP film was 1.86 times more than that of the NIP. All these results proved that Lys-MIP film possessed high adsorption capacity and excellent selectivity. This material has great potential for separation of Lys in real samples.

Keywords: Egg white, Lysozyme purification, Multi-wall carbon nanotubes, Molecular imprinting, Protein recognition, Surface imprinting