variable region

variable region

noun

Definition of VARIABLE REGION

: the part of the polypeptide chain of a light or heavy chain of an antibody that ends in a free amino group −NH₂, that varies greatly in its sequence of amino acid residues from one antibody to another, and that probably determines the conformation of the combining site which confers the specificity of the antibody for a particular antigen—called also variable domain; compare constant region

Illustration of VARIABLE REGION