Question

Antigen binding site is present on which terminal of peptide chain in antibodies

• A. N-terminal
• B. C-terminal
• C. Either N- or C-terminal
• D. In between N- and C-terminals

Answer 1

The correct option is A N-terminal

• There is a unique antigen binding site in each antibody that is compatible with specific antigens.
• Antigen binding site is present on the N-terminal of peptide chain in antibodies.
• Two identical fragments of Y-shaped molecules possess the antigen-binding sites and are thus named fragment-antigen-binding (Fab).
• This site includes the variable regions of both the heavy and the light chain.
• The antigen-binding sites bind to the specific antigens in a lock and key pattern, forming an antigen-antibody complex.
  

Hence, option A is correct.