Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
antigen-binding site
References
Images
Diagram showing how the flexible hinge regions of antibody molecules allow them to adjust for better binding to antigens and enable cross-linking, forming large antigen-antibody complexes. Antibodies are depicted binding to antigenic determinants on spherical antigens, illustrating both single and cross-linked interactions.
Britannica AI Icon

antigen-binding site

biochemistry
Also known as: antibody-combining site
Written by
The Information Architects of Encyclopaedia Britannica

The Information Architects maintain a master list of the topics included in the corpus of  Encyclopædia Britannica, and create and manage the relationships between them.
The Information Architects of Encyclopaedia Britannica
Last updated

Quick Summary

Diagram showing how the flexible hinge regions of antibody molecules allow them to adjust for better binding to antigens and enable cross-linking, forming large antigen-antibody complexes. Antibodies are depicted binding to antigenic determinants on spherical antigens, illustrating both single and cross-linked interactions.
Diagram of the hinge region of an antibody molecule (A) The hinge region of an antibody molecule opens and closes to allow better binding between the antibody and antigenic determinants on the surface of an antigen. (B) Hinge flexibility also facilitates the cross-linking of antigens into large antigen-antibody complexes.

The antigen-binding site is a crucial part of an antibody, a protein produced by the immune system to identify and neutralize foreign substances called antigens. This site is located at the tips of the Y-shaped antibody molecule and is formed by portions of both the heavy and light polypeptide chains.12

The primary function of the antigen-binding site is to recognize and attach to a specific part of an antigen, known as an epitope. This recognition occurs when the shape of the epitope is complementary to the shape of the binding site, allowing them to fit together like puzzle pieces. This binding is essential for activating the immune response and removing the foreign substance from the body. Each antibody has at least two identical antigen-binding sites, and these sites vary greatly among different antibodies, enabling the immune system to recognize a vast array of antigens.21

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
3 Britannica Sources
  1. immune system - Basic structure of the immunoglobulin molecule
  2. antibody
  3. binding site

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.