The utility of photo-affinity labels as "mapping" reagents. A study of sub-populations of a specific rabbit antibody by using structurally related photo-affinity reagents.
A specific rabbit antibody against the 4-azido-2-nitrophenyl determinant was photo-labelled by the homologous hapten epsilon-(4-azido-2-nitrophenyl)-l-lysine, and by the close structural isomer epsilon-(5-azido-2-nitrophenyl)-l-lysine. The extents of covalent labelling of the antibody-binding site were assessed by using radioactive haptens and exhaustive displacement dialysis, which leaves the unlabelled sites empty but largely intact. A single photolysis of hapten-antibody complex suffices to label those sites that are capable of being labelled. Although there is considerable overlap among sub-populations of antibody that will bind the two haptens non-covalently, sites that can be covalently labelled by one reagent cannot be labelled by the other.
D000818:Animals; D000906:Antibodies / Q000032:analysis*; D000936:Antigen-Antibody Complex; D001386:Azides; D001666:Binding Sites, Antibody; D002850:Chromatography, Gel; D003956:Dialysis; D006241:Haptens; D008239:Lysine / Q000031:analogs & derivatives; D009682:Magnetic Resonance Spectroscopy; D009596:Nitrophenols; D010777:Photochemistry; D010782:Photolysis; D011485:Protein Binding; D011817:Rabbits / Q000276:immunology; D013056:Spectrophotometry, Ultraviolet; D014316:Tritium
D000906:Antibodies; D000936:Antigen-Antibody Complex; D001386:Azides; D006241:Haptens; D009596:Nitrophenols; D014316:Tritium; D008239:Lysine