Explain the structure of immunoglobulin with suitable diagram.

Explanation

(i) An antibody molecule is Y shaped structure that has four polypeptide chain (Two identical light chains (L) of molecular weight 25000 Da and two identical heavy chains (H) of molecular weight 50000 Da).
(ii) The polypeptide chains are linked together by di -sulphide (S-S) bonds.
(iii) One light chain is attached to each heavy chain and the two heavy chains are attached to each other to form a Y shaped structure. Hence an antibody is represented by `H_2L_2`.
(iv) The heavy chains have flexible hinge regions at their middles.
(v) Each chain has two terminals (C-terminal and N-terminal) and two regions (variable regions (v) and constant region(c)).