The pairs of chains are known as heavy and light chains. They are usually drawn as a Y shape but as you will see in the following demonstration this is not entirely true. Press this button to load the structure of the antibody but only the backbone of the enzyme is shown so that you can see its general shape. This graphic is 'live' and you can manipulate it with the mouse. Drag it to rotate it.
Antibodies are the bodies way of fighting infection.
The antibody contains a specific site known as the antigen binding site which binds to the invading organism. Antibodies are glycosylated . This means that they have a small number of sugars added to the protein chain. The antigen is part of the coat of an HIV virus. Note that this structure was obtained from an antibody fragment which contains one light chain and a fragment of heavy chain.