The advantages of photogenerated reagents

A photoaffinity reagent (Fig. 1.1.) is a ligand that is chemically inert but conceals a highly reactive intermediate that is unmasked by irradiation with 

an inert ligand is desirable because it allows the investigator to perform important preliminary experiments with ease. Binding measurements and assays of biological activity are straightforward and unusual experiments that might not be feasible with a chemically reactive molecule can be done. For example, photolabile molecules may be used as haptens for antibody production and the hapten-immunoglobulin interaction subsequently explored (Fleet et al., 1969). 

Finally, these properties permit the use of photoaffinity reagents in experiments in which kinetic phenomena are examined, and it has proved possible to extend the resolution to the millisecond time-scale. 

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