Table of Contents
What are glycoproteins and what is their purpose?
Glycoproteins are molecules that comprise protein and carbohydrate chains that are involved in many physiological functions including immunity. Many viruses have glycoproteins that help them enter bodily cells, but can also serve to be important therapeutic or preventative targets.
How do you know if a site is glycosylation?
The standard approaches (Figure 1) to determine site-specific glycosylation are to employ a combination of specific enzymatic proteolysis (usually with trypsin), fractionation of glycopeptides (most often by liquid chromatography or affinity chromatography) and glycopeptide analysis by MS [7-11].
How is protein glycosylation measured?
For detection of glycosylated proteins, two types of methods are generally used: staining and affinity-based methods.
- 2.1. Staining Procedures. A basic, simple method to determine whether a protein is glycosylated is to resolve it on SDS-PAGE and to stain the gel for glycoproteins.
- 2.1. Affinity-Based Procedures.
What is the role of glycoprotein in cell recognition?
Cell recognition proteins are glycoproteins that have several functions, such as recognition of pathogens . These proteins serve as a cell’s “identity badge”. If the cells of you immune system see a cell in your body that doesn’t have the correct glycoproteins sticking out of it.
How do you analyze glycosylation?
Glycosylation analysis can be tackled using three different approaches: (i) characterization of glycans in intact glycoproteins, (ii) characterization of glycopeptides and (iii) structural analysis of chemically or enzymatically released glycans.
Where is glycoprotein produced?
the Golgi apparatus
Glycoprotein synthesis occurs in two organelles in sequence such as endoplasmic reticulum and the Golgi apparatus.
What are examples of glycoprotein?
Some of the examples where glycoproteins are found naturally:
- collagen.
- mucins.
- transferrin.
- ceruloplasmin.
- immunoglobulins.
- antibodies.
- histocompatibility antigens.
- hormones (e.g. follicle-stimulating hormone, luteinizing hormone, human chorionic gonadotropin, thyroid-stimulating hormone, erythropoietin, alpha-fetoprotein)
What proteins are used for cell recognition?
Recognition proteins: These proteins, called glycoproteins (glyco = sugar) have complex carbohydrates attached to them. These form the identification system that allows your body cells to recognize each other as “self” instead of “invader.”
How many types of glycoprotein are there?
There are three types of glycoproteins based on their structure and the mechanism of synthesis: N-linked glycoproteins, O-linked glycoproteins, and nonenzymatic glycosylated glycoproteins.
What is the purpose of glycation?
Glycosylation is an important and highly regulated mechanism of secondary protein processing within cells. It plays a critical role in determining protein structure, function and stability. Structurally, glycosylation is known to affect the three dimensional configuration of proteins.
How do you identify glycans?
Glycans do not contain fluorophores and thus must be labeled with fluorescent tags prior to analysis. Labeling is performed at the reducing end of the glycan by reductive amination, with the most common labels being 2-aminobenzamide (2-AB) or 2-aminobenzoic acid (2-AA).
Why is glycan analysis important?
The glycan moieties attached to the proteins can directly affect protein stability, bioactivity, and immunogenicity. Therefore, glycan variants of a glycoprotein product must be adequately analyzed and controlled to ensure product quality.
What databases can be linked to the glycosmos?
The glycans can be linked to the JCGGDB database and the references are linked to PubMed for further interest. Although some interactions require confirmation, it provides a lead for further investigation of correlations between pathogen and host cells. Currently, the data of PACDB has been summarized in the GlyCosmos.
Why do we need a fully integrated database for glycan analysis?
Thus, fully integrated databases collecting the data on glycan-related molecules, glycogenes and their biological functions are needed. In past decades, with the development of various analytical techniques in glycomics and glycoproteomics, many databases with huge information are emerging.
What is the best method for the identification of complex glycans?
A variety of technologies such as hydrophilic chromatography, hydrazide chemistry, lectin chromatography, or metabolic labeling have been widely used [17,47,48,49,50,51]. Sequentially, the complex glycans are removed or shortened by glycosidase treatment or chemical approaches and usually a unique tag is left or labeled at the glycosylation site.