Confused and have questions? We’ve got answers. With Chegg Study, you can get step-by-step solutions to your questions from an expert in the field. If you rather get 1:1 study help, try 30 minutes of free online tutoring with Chegg Tutors.


From Biology-Online Dictionary | Biology-Online Dictionary
(Redirected from Glycoproteins)
Jump to: navigation, search


noun, plural: glycoproteins

Any of the conjugated proteins, characterized by having one or more covalently-linked carbohydrate residues


Glycoconjugates are carbohydrates that are covalently linked to another biomolecule via glycosylation and the carbohydrate constituent of the complex is called a glycan. Examples of glycoconjugates are glycoproteins, glycopeptides, peptidoglycans, glycosides, glycolipids, and lipopolysaccharides.

A glycoprotein pertains to any protein covalently attached to a carbohydrate unit through the process of glycosylation. Some of the common carbohydrate constituents of glycoproteins are β-D-glucose, β-D-galactose, β-D-mannose, α-L-fucose, N-acetylglucosamine, N-acetylgalactosamine, N-acetylneuraminic acid, and xylose. The carbohydrate constituent is attached to the protein via the -OH group of serine or threonine (i.e. O-glycosylated) or via the amide NH2 of asparagine (i.e. N-glycosylated).

Some of the examples where glycoproteins are found naturally:

While technically describing conjugates in which the carbohydrate is less than 4 percent by weight, the term is often used generically to include the mucoproteins and proteoglycans. However, differences in the usage of the terms: glycoprotein, proteoglycan, peptidoglycan, and glycopeptide exist, and therefore, prudence in the usage of these terms has to be exercised.

For instance, proteoglycans may be regarded as a subset of glycoproteins since both of them have a protein core. However, there are differences in several aspects. In structure, glycoproteins have carbohydrate chains attached to a polypeptide side chain whereas proteoglycans have glycosaminoglycan chains attached to the polypeptide. Glycoproteins have lower percentage of non-protein content by weight than proteoglycans (which, in turn, have higher, about 50-60%).

See also:

Related term(s):