Composite Nano Materials Used In Sugar Peptide And Phosphorylated Peptide Selective Enrichment Of Mass Spectrum Identification Research New Methods

Protein glycosylation is one of the most important post-translational modification,which has a momentous effect on the protein’s structures and functions,such as protein folding, cell division, signal transduction, inflammation, tumorigenesis, differentiation, as well as cell-cell recognition.For this reason,it has great significance on biological sciences and clinical research to study glycoproteins. it is difficult to analyze glycoprotein because of the presence of other highly abundant nonglycoproteins in complex biological samples. Consequently, isolation and enrichment of glycosylated proteins is generally required firstly.Only we isolate and enrich the specified glycoproteins or all the glyproteins efficiently,can we identify more glyproteins advantageously.In the chapter one,we introduced the improtance of glycoprotein and its related properties.The development of glycoproteome and the usual enrichment methods of glycoproteins were also introduced.The efficient separation and enrichment of glycoprotein from complex biological samples is the key and difficult point of glycoproteome research. Using boronic acid-functionalized magnetic beads to isolate and enrich glycosylated peptides and proteins have been a hot point in the glycoproteome research in recently years. In chapter two, the4-mercaptophenylphenylboronic acid-functionalized magnetic iron oxide nanoparticles were synthesized.we optimized the enrichment conditions and the isolation method for the selective capture of glycoproteins from unfractionated protein mixtures.After the enrichment efficiency being investigated, we apply it to the research of glycoprotein in rat’s serum.Protein phosphorylation is one of the most common and important post-translational modifications. In mammalian cells, at least one-third of all proteins are phosphorylated it is critical in many aspects of cellular functions such as signal transduction.Like glycoprotein,the research of phosphoprotein meet similar challenges. Most phosphorylated proteins are low in abundance and the mass spectrum signal of phosphopropeptide can be easily suppressed by other nonphosphopropeptides.Glycosylation and phosphorylation usually exist simultaneously in the same protein. If we selectively enrich glycoproteins,we will lost the phosphoproteins. On the other hand, if we selectively enrich phosphoproteins, we will lost the glycoproteins. In the complex biological samples,it’s of a great improtance to enrich proteins of different post-translational modifications simultaneously,which can help us understand the influences to proteins brought by the existance of different post-translational modifications.The amino modified nano magnetic beads are easily synthesized,which have good repeatability.Because of its magnetism,it can be isolated easily. In strong acid solution, aminos will be electropositive by combining hydrogen ions,while phosphopeptides are electronegative. So we can make use of the electrostatic attraction between them to enrich phosphopeptides.In addition, the amino modified nanomagnetic beads are hydrophilic,while glycopeptides also have a good hydrophilicity.So we could utilize the hydrophilic interaction to enrich glycopretides.Through the adjustment of the solution’s pH, we’re able to enrich phosphopeptides and glycopeptides consecutively by different methods.In chapter three, we synthesize the amino modified nano magnetic beads and optmized the enrichment conditions of phosphopeptides and glycopeptides severally. In the end,we succeed in enriching phosphopeptides and glycopeptides consecutively through standard peptides.