Separation And Enrichment Of Glycoprotein By Functionalized Magnetic Nanoparticles And The Synthesis Of Sialic Acid Derivatives

Protein glycosylation is one of the most important post-translation modifications, has crucial effect on structure and function. Glycoproteins regulate many important biological processes. Many clinical biomarkers and therapeutic targets are glycoproteins. Therefore, the study of glycoproteins has very important biological significance.The targets of glycoproteiomics research are complex biological samples. Low abundance and microheterogenity of glycoproteins, make the separation and enrichment of glycoproteins difficult. The methods applied in glycoprotein separation and enrichment have been introduced, with emphasis on chemical methods.The article is focus on the separation and enrichment of glycoproteins. The aminooxy functionalized magnetic nanoparticles prepared by our group was applied to separate and enrich of glycoproteins. The functional group, can selectively reactive with the aldehyde group generated by oxidation of the glycol side chain of sialic acid on glycoprotein and attach glycoproteins to particles. Attacted glycoprotein can easily separate by magnetic power. The disulfide bond can be cleaved by reducing agent without break the glycosidic linkage and lost the information of glycosidic fragment. The reaction condition such as temperature, time, catalyst,reducing agent, pH value, and concentration of oxidative have been discussed, and the optimized condition was established.In the third part, using sialic acid as starting material, through selective protection and the deprotection, 9-aldehyde and 9-azide was introduced into sialic acid. The next step of the study is to introduce the 9-azido sialic acid to cell by metabolic incorporation, then enrich the labeled sialoglycoproteins through click chemistry.In this article, the method of selective separation and enrichment of glycoproteins was established. Provide certain references for subsequent research.