Preparation and characterization of photoactivable heterobifunctional fluorescent reagents

Two new photoactivable heterobifunctional reagents, 1-azido-5-naphthalene sulfonyl chloride (ANS-C1) and the N-hydroxysuccinimide ester of 1-azido-5-naphthalene sulfonyl aminopropionate (NHS-ANS-AP), were synthesized and characterized. The reagents were applicable to the group-directed modification of ligands. Upon exposure to ultraviolet light, the non-fluorescent modified ligands generated reactive nitrene intermediates which could react with neighboring molecules to form fluorescent products. This was demonstrated by the covalent modification of bovine serum albumin with ANS-AP by photolysis. NHS-ANS-AP was used for the preparation of a photore-active invertebrate lectin.