磁性碳基复合材料在蛋白质固定化酶酶解中的应用

In this article, we synthesized a functional material, GO-Fe3O4-TiO2, a carbon-based magnetic metallic oxide ternary composite. Through investigation, we found out the optimized preparation approach of this material. First, Fe3O4 was loaded onto GO through physical adsorption and amidation with the help of EDC and NHS. Next TiO2 was added by the approach of tetrabutyl titanate hydrohysis under heating and stirring. Experimental obvervation and Scanning Electron Microscope (SEM) images showed that properly-sized inorganic particles (both Fe3O4 and TiO2) were dispersed evenly on the surface of GO. Then this composite material was applied in immobilized enzyme enzymolysis and phosphopeptide enrichment. Though this GO-based material exhibited excellent performance in enzyme upload due to the hydrophobic interaction between GO and enzymes, MALDI-TOF MS (Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry) results turned out to be abnormal, with more missed cleavages and low intensity of peptides, which we estimated was caused by the chemical interaction between GO and enzyme, leading to the reduction and even disappearance of the activity of the enzyme. However, the performance of this ternary composite material in phosphopeptide enrichment was excellent. Taking beta-Casein as an model analyte, the detection limit of this method could reach as low as 40 fmol, showing the great advantage of this material in the application of phosphopeptide enrichment.