Antibodies are Y-shaped chemicals made up of polypeptides and carbohydrates. Its structure is as follows.
- Heavy and light chains: Each antibody has four polypeptide chains. Two light chains and two heavy chains. The two light chains are called L chains and the two heavy chains are H chains. L chains are two short. Its molecular weight is 20,000-25,000 daltons. It is composed of 220 amino acids. H chains are two large. Its molecular weight is 50,000-70,000 daltons. It is composed of 440 amino acids.
- Disulfide Bonds: Each antibody has 3 disulfide bonds. There is one disulfide bond between the heavy chains and two disulfide bonds between the heavy and light chains. Antibodies look like the letter Y when joined by brackets.
- Constant and variable regions: Each antibody has two regions. Fixed region and variable region. The posterior part of the antibody is called the constant or target region. The amino acids of the constant region are not changed.
The leading edge of the antibody is called the constant or variable region. The structure of this region changes to capture the antigen. It has a notch or paratop at its tip to catch germs. Antibodies bind to bacteria in a lock and key manner. In this case the key is the paratope and the lock is the antigen (bacteria).