Specific Binding Activity of Isolated Light Chains of Antibodies

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Science  11 Aug 1967:
Vol. 157, Issue 3789, pp. 707-709
DOI: 10.1126/science.157.3789.707


Free light chains isolated from specifically purified antibody have been shown to bind specific hapten. This proves that part of the binding site does exist on the light chain. The light chains were obtained from antibody directed against the 4-azonaphthalene-1-sulfonate group, and the binding of the simple hapten 4-anilinonaphthalene-1-sulfonate was determined by the fluorescence-enhancement technique. Since this hapten undergoes a striking increase in fluorescence on binding to light chains (and also on binding to specific antibody), the presence of small amounts of bound hapten could be determined, even in the presence of the high concentrations of unbound hapten required because of the low binding constant.