2.4.1 Research on glycoproteins
Protein is the executor of life activities. During the study of proteins, researchers found that proteins have many modifications. Among these modifications, glycosylation is very common, and more than 50% of the proteins found so far have glycosylation. Glycans are the sugar components of glycoproteins, including sugar groups and various types of branching structures, composed of various sugars, such as glucose, galactose, mannose and rhamnose. Polysaccharides complete the glycosylation modification of proteins by connecting oxygen on specific amino acid residues to proteins. One way to study glycomics is to analyze glycoproteins.
For glycoproteins, there are the following research methods:
  1. Glycosyl capture: Lectin can specifically recognize one sugar or a variety of sugars to agglutinate glycoproteins, which can be used to obtain crude glycoproteins[20].
  2. Fluorescent dyes: Fluorescent dyes are usually used in combination with high-throughput two-dimensional gel electrophoresis for protein discovery and identification[21].
  3. Liquid chromatography: Separation of glycoproteins by SEC-HILIC-CapLC workflow and other techniques can be used to construct a three-dimensional liquid phase glycan profile to obtain glycan structure information[22].
  4. Mass spectrometry: Mass spectrometry is used to analyze the cleavage rules of protein skeleton and sugar skeleton, which can be used for glycosylation site analysis[23-25].
  5. Magnetic resonance: Through the change of atomic energy transition, accurate calculation of composition, ring size and abnormal carbon conformation can be used to accurately confirm the structure of sugar chain[26].