HIGH-EFFICIENCY PHOTOLABELING OF HUMAN SERUM-ALBUMIN AND HUMAN GAMMA-GLOBULIN WITH [C-14] METHYL 4-AZIDO-2,3,5,6-TETRAFLUOROBENZOATE

The efficiency of photolabeling of HSA and IgG with [C-14]methyl 4-azi do-2,3,5,6-tetrafluorobenzoate has been studied using size exclusion c hromatography in conjunction with liquid scintillation counting Labeli ng efficiencies of 78% for HSA and 82% for IgG have been determined. T he extent of bond insertion into proteins exceeds the C-H insertion ef ficiency in cyclohexane with less wastage into anilinium and azo side products. These results suggest that the photoprobe accesses hydrophob ic regions of both proteins prior to photolysis.