PRESERVATION OF IMMUNOREACTIVITY IN THE PHOTOLABELING OF THE B72.3 HUMAN-ANTIBODY

A versatile photochemical method of labeling human antibodies is descr ibed. Labeling is achieved by photolyzing 4-azido-2,3,5,6-tetrafluoro- C-14-methylbenzoate and the B72.3 human antibody in a buffer at physio logical pH. The photochemically produced nitrene presumably inserts in to bonds in the hydrophobic part of the antibody resulting in >75% att achment of the photoprobe. An immunoassay of B72.3 with mucin (B72.3 a ntigen) reveals >97% retention of immunoreactivity and suggests that p hotochemical labeling is a viable alternative for the conjugation of b iomolecules.