Some Functions of Glycoproteins

• STRUCTURAL (Collagens and many other proteins in the extracellular matrix [the connective tissue between cells] are glycoproteins)
• LUBRICANTS (Mucins)
• TRANSPORT (Plasma proteins like Transferrin [Iron] or Ceruloplamin [copper])
• IMMUNOLOGIC (Immunoglobulins or antibodies--all antibodies are glycoproteins)
• SOME HORMONES (Thyroid Stimulating Hormone, Human chorionic gonadotropin produced during pregnancy)
• SOME ENZYMES (Alkaline phosphatase)
• RECEPTORS (For various hormones & drugs, etc. attached to our cells)
• FERTILIZATION (Sperm meets egg; glycoproteins on the egg & sperm are involved)
• CELL-TO-CELL COMMUNICATION (How a hormone [e.g. insulin] from another tissue affects its target organs; first it interacts with a glycoprotein receptor)
• CELL-CELL ADHESION (How cells align & stick to each other; implications for cancer)