Concanavalin A immobilized magnetic poly(glycidyl methacrylate) beads for antibody purification

Recent Advances in Lectin-Based Affinity Sorbents for Protein Glycosylation Studies

Glycosylation is one of the most significant post-translational modifications occurring to proteins, since it affects some of their basic properties, such as their half-life or biological activity. The developments in analytical methodologies has greatly contributed to a more comprehensive understanding of the quantitative and qualitative characteristics of the glycosylation state of proteins. Despite those advances, the difficulty of a full characterization of glycosylation still remains, mainly due to the complexity of the glycoprotein and/or glycopeptide mixture especially when they are present in complex biological samples. For this reason, various techniques that allow a prior selective enrichment of exclusively glycosylated proteins or glycopeptides have been developed in the past and are coupled either on- or off- line with separation and detection methods. One of the most commonly implemented enrichment methods includes the use of lectin proteins immobilized on various solid supports. Lectins are a group of different, naturally occurring proteins that share a common characteristic, which concerns their affinity for specific sugar moieties of glycoproteins. This review presents the different formats and conditions for the use of lectins in affinity chromatography and in solid phase extraction, including their use in dispersive mode, along with the recent progress made on either commercial or home-made lectin-based affinity sorbents, which can lead to a fast and automated glycosylation analysis.

Cryogels with affinity ligands as tools in protein purification

Affinity chromatography is one of the well-known separation techniques especially if high purity is desired. Introducing ligands on monolithic structure gives the possibility for purifying complex media such as plasma and crude extract. This chapter is focusing on the preparation of cryogels as monolithic column and immobilization of concanavalin A on its surface as ligand for capturing the glycoprotein horseradish peroxidase.

Polyethyleneimine-modified graphene oxide nanocomposites for effective protein functionalization

A facile method to prepare a biocompatible graphene oxide (GO)-based substrate for protein immobilization was developed to overcome the drawbacks of GO, such as the strong electrostatic and hydrophobic interactions which could potentially alter the conformation and biological activity of proteins. The GO was coated with hydrophilic branched polyethyleneimine (BPEI), while Concanavalin A (Con A) as a model lectin protein was employed to fabricate the functionalized composites to evaluate the feasibility of this strategy. The composites exhibit an extremely high binding capacity for glycoproteins (i.e. IgG 538.3 mg g(-1)), which are superior to other immobilized materials. Moreover, they can work well in 500-fold non-glycoprotein interference and even in complex biological samples. All these data suggest that the GO@BPEI composites will have great potential as scaffolds for proteins fully exerting their biofunctions.

Surface imprinting approach for preparing specific adsorbent for IgG separation

In this study, we focused our attention on preparing of a new adsorbent for specific separation of immunoglobulin G (IgG). In this respect, we applied core-shell surface imprinting approach. Silica microspheres were selected as core-material to prepare specific surface imprinted polymer against IgG. Silica surface was activated via acidic treatment and modified with 3-methacryloyloxypropyl trimethoxysilane (MPTMS). Then, IgG molecules were imprinted on the surface of microspheres by using N-methacryloyl-L-aspartic acid as complexing/functional monomer. The core-shell silica microspheres were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, thermo gravimetric analysis and zeta size analysis. Then, the microspheres were used for the separation of IgG from aqueous solution to evaluate/optimize conditions. The effect of parameters such as concentration, pH, ionic strength, and temperature on the separation of IgG were evaluated in their relevant ranges. The maximum IgG adsorption capacities of IgG-imprinted and non-imprinted core-shell silica microspheres were found to be 15.43 and 9.43 mg/g, respectively, at pH 6.0 phosphate buffer. 1.0 M NaCl was used as a desorption agent. Selectivity of the imprinted microspheres was also investigated by using human serum albumin and haemoglobin as competitor molecules.