Glycoproteins are organic compounds that are composed on both a protein and carbohydrate bonded together. This covalent bonding occurs in many life forms but they are prevalent and imperative in mammals. In glycoproteins, the attached carbohydrate may stabilize the protein, help the protein achieve and maintain proper geometry and promote solubility and viscocity in the cell membrane.

Though many proteins released into the blood are glycoproteins, one set of glycoproteins also carry blood group determinants. The carbohydrate portion of the glycoprotein is usually a small sugar component made up of individual monosaccharide units. This glyconutrient component may be a combination of up to seven of the many naturally occurring sugar molecules in mammals including glucose, glucosamine, galactose, galactosamine, mannose, fucose, and sialic acid (a derivative of glucosamine).

Glycoproteins such as ovalbumin (found in egg white) and blood plasma is highly viscous in nature. Human saliva contains the glycoprotein mucin. Certain Antarctic fishes survive near-freezing temperatures due to a globular glycoprotein that acts as a freezing-point depressant. Glycoproteins are important for immune cell recognition in mammals.

A few examples of glycoproteins include:

• Antibodies (immunoglobulins) that interact directly with antigens
• Major histocompatibility complex (or MHC) molecules that interact with the T-cells as part of an adaptive immune response
• Components of the zona pellucida is important for sperm-egg interaction

Glycoproteins help many systems within the human body to function properly and optimally and deficiencies can be responsible for a whole spectrum of diseases, conditions and ailments.