A new radiolabeled, bifunctional photoaffinity cross-linking reagent,
N-succinimidyl p-benzoyl-[2,3-H-3(2)]dihydrocinnamate, has been synthe
sized in high yield and with high specific activity. This reagent can
be used to append the benzophenone photophore to amino groups of small
molecules, such as O-aminoalkylinositol polyphosphates and polypeptid
es. The resulting tritiated photoaffinity labels can be purified and m
anipulated in ambient light and can be activated at 360 nm.