Animal Biotechnology

COMPLEX MACROMOLECULES

• Many macromolecules contain covalent or non-covalent associations of more than one of the major classes of large biomolecules. For example, nearly all enzymes are proteins, but some have noncovalently attached RNA component which is essential for catalytic activity. Association of nucleic acid and protein are known as nucleoproteins.
• Glycoproteins contain both protein and carbohydrate components. Glycosylation is the commonest form of post-translational modification of proteins.
• Proteoglycans (mucoproteins) are large complexes (> 10⁷ Da) of protein and mucopolysaccharide found in bacterial cell walls and in the extracellular space in connective tissue. Proteoglycans act as lubricants and shock absorbers in extracellular spaces.
• Lipid-linked proteins have a covalently attached lipid component. This is usually a fatty acyl (e.g. myristoyl or palmitoyl) or isoprenoid (e.g. farnesyl or geranyl group).