Proteins are covalently linked linear polymer of amino acids.
Proteins and their functions
Proteins occur in great variety and size varying from small peptides of the molecular mass of about 2000u to large polymers of molecular mass in millions. Proteins are produced and occupy the largest portion of cells. Each protein is unique by the genetic information it represents.
Accordingly, they perform different functions- structural support, hormones, antibodies, catalytically active enzymes, signal receptors, transporters of specific substances in and out of cell walls etc.
- A protein-polymer chain is seldom linear.
- Each protein chain adopts a unique final folded structure that can be understood as developing from a linear primary structure, through, secondary, tertiary and finally to a quaternary structure.
- Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached in long chains