Selective separation of bovine hemoglobin using magnetic mesoporous rare-earth silicate microspheres

Selective separation of heme proteins and peptides from complicated biological samples before comprehensive identification and characterization of intact biomolecules which are low stoichiometry is indispensable for ongoing proteomics. Here, three magnetic mesoporous rare-earth silicate (rare-earth = Er, Tm, Yb) microspheres prepared by facile solvothermal method were used as novel adsorbents for the selective isolation of bovine hemoglobin (BHb), and magnetic mesoporous ytterbium silicate showed apparent adsorption efficiency in isolating BHb with a adsorption capacity of 304.4 mg/g after the comparison. The retained BHb could be eluted by using Na2CO3 as stripping reagent. Meanwhile, Circular dichroism spectra illustrated that the microspheres posed no effect on the secondary structure of BHb. The resultant magnetic particles were characterized by transmission electron microscope, scanning electron microscope, x-ray powder diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy, N-2 adsorption - desorption isotherm and zeta potential. The as-prepared magnetic microspheres showed high specificity for the separation of BHb from bovine plasma as corroborated by SDS-PAGE and MALDI-TOF MS analysis, which would be expected to possess potential application in isolation of other heme proteins in complex biological samples.