AskDefine | Define glycoprotein

Dictionary Definition

glycoprotein n : a conjugated protein having a carbohydrate component

User Contributed Dictionary

English

Noun

  1. A protein with covalently bonded carbohydrates

Extensive Definition

Not to be confused with peptidoglycan.
Glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending extracellularly, the extracellular segments are often glycosylated. Glycoproteins are often important integral membrane proteins, where they play a role in cell-cell interactions.

N-glycosylation and O-glycosylation

There are two types of glycosylation:

Monosaccharides

Monosaccharides commonly found in eukaryotic glycoproteins include:
The sugar group(s) can assist in protein folding or improve proteins' stability.

Examples

One example of glycoproteins found in the body is mucins, which are secreted in the mucus of the respiratory and digestive tracts. The sugars attached to mucins give them considerable water-holding capacity and also make them resistant to proteolysis by digestive enzymes.
Glycoproteins are important for white blood cell recognition, especially in mammals. Examples of glycoproteins in the immune system are: Other examples of glycoproteins include:
  • components of the zona pellucida, which surrounds the oocyte, and is important for sperm-egg interaction.
  • structural glycoproteins, which occur in connective tissue. These help bind together the fibers, cells, and ground substance of connective tissue. They may also help components of the tissue bind to inorganic substances, such as calcium in bone.
Soluble glycoproteins often show a high viscosity, for example, in egg white and blood plasma.

Functions

Analysis

A variety of methods used in detection, purification, and structural analysis of glycoproteins are

References

See also

External links

glycoprotein in Catalan: Glicoproteïna
glycoprotein in Czech: Glykoproteiny
glycoprotein in Danish: Glykoprotein
glycoprotein in German: Glykoprotein
glycoprotein in Spanish: Glicoproteína
glycoprotein in French: Glycoprotéine
glycoprotein in Italian: Glicoproteina
glycoprotein in Hebrew: גליקופרוטאין
glycoprotein in Macedonian: Гликопротеин
glycoprotein in Malay (macrolanguage): Glikoprotein
glycoprotein in Dutch: Glycoproteïne
glycoprotein in Japanese: 糖タンパク質
glycoprotein in Norwegian: Glykoprotein
glycoprotein in Occitan (post 1500): Glicoproteïna
glycoprotein in Polish: Glikoproteiny
glycoprotein in Portuguese: Glicoproteína
glycoprotein in Russian: Гликопротеины
glycoprotein in Simple English: Glycoprotein
glycoprotein in Finnish: Glykoproteiini
glycoprotein in Swedish: Glykoprotein
glycoprotein in Turkish: Glikoprotein
glycoprotein in Ukrainian: Глікопротеїни
glycoprotein in Chinese: 糖蛋白
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