a configuration in the upper branches of the Y of an antibody molecule, unique in each antibody type, that binds with the determinant of a specific antigen.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
The portion of the amino (NH2) terminal of an antibody's heavy and light chains having a variable amino acid sequence. The structure of the variable region determines the antigenic specificity of the antibody. Compare constant region.
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