Direct matrix-assisted laser desorption ionization time-of-flight mass spectrometric analysis of lysozyme contained in hen egg white

Bisphosphonated-immobilized porous cellulose monolith with tentacle grafting by atom transfer radical polymerization for selective adsorption of lysozyme

Here, a m-xylene bisphosphonate immobilized tentacle-type cellulose monolith (BP-PCM) is prepared by atom transfer radical polymerization for lysozyme purification. In the preparation, the m-xylene bisphosphonate was anchored glycidyl methacrylate and then polymerized to enhance the flexibility of the ligands to improve lysozyme adsorption capacity, and glycerol monomethacrylate serves as spacer to further optimize the layers structure and ligands density of the grafted tentacles for satisfactory adsorption capacity. The maximum static and dynamic adsorption capacity (10% breakthrough) of BP-PCM reach to 169.6 and 102.6 mg mL^-1, respectively. Moreover, BP-PCM displays weak nonspecific adsorption and is able to successfully enrich lysozyme from diluted chicken egg white, indicating the excellent selectivity. The results demonstrated that BP-PCM is promising for use as high-capacity protein chromatography.

Direct Detection of Lysozyme in Viscous Raw Hen Egg White Binding to Sodium Dodecyl Sulfonate by Reactive Wooden-tip Electrospray Ionization Mass Spectrometry

Direct characterization of native protein binding to ligands in raw biological samples is a challenging task, because the ligand solution might induce proteins to aggregation, flocculation and denaturation. In this work, we developed a reactive wooden-tip electrospray ionization mass spectrometry (ESI-MS) for formation and characterization of protein-ligand complexes upon rapid mixing in electrospray droplets. Raw viscous hen egg white (HEW) was directly loaded onto a wooden tip to induce spray ionization, and sodium dodecyl sulfonate (SDS) solution was directly loaded into the HEW spray by a pipette tip, and thus lysozyme-DS complexes were then formed in the electrospray droplets and were detected subsequently by mass spectrometry. The new approach was successfully applied to investigate interaction of SDS and native lysozyme in electrospray droplets of standard solution and raw egg white. Our results showed that wooden-tip ESI-MS is a promising method to form and characterize protein-ligand complexes.