Facile and Selective Nanoscale Labeling of Peptides in Solution by Using Photolabile Protecting Groups

For the selective labeling of peptides, a novel strategy was developed that combines the advantages of solid-phase peptide synthesis with the flexibility of labeling reactions in solution. To direct a label at a distinct position within the peptide sequence, other reactive positions are blocked with photolabile protecting groups that could be easily removed after the labeling reaction. Therefore selective labeling may become feasible for the first time even in nanomol amounts.