Requirements for a useful photoactivatable reagent

An ideal photoaffinity labeling reagent would meet the criteria listed below, and subsequently discussed in more detail for each class of reagent. 

Some nitrene and carbene precursors that have been used to label biological molecules 

Imine formation predominates (but see Stoffel et al., 1982 Stoffel and Metz, 1982) 

Highly reactive nitrenes (Lwowski, 1970). Rarely used because of low e, but see Vaver et al. (1979). 

Lwowski (1970). Have been incorporated into phospholipids (Stoffel et al., 1978). Not generally recommended because of rearrangements and low e. 

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