light chain n either of the two smaller of the four polypeptide chains that are subunits of antibodies called also L chain compare HEAVY CHAIN
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any of the smaller polypeptide chains of antibody molecules, two identical light chains occurring (with two identical heavy chains) in each immunoglobulin monomer. There are two types, designated κ and λ, both occurring in all immunoglobulin classes (in a ratio of about two κ chains to one λ chain in humans). Light chains have two homology regions of about 110 amino acid residues: one variable region (VL) and one constant region (CL). Called also L c. See immunoglobulin.Medical dictionary. 2011.