Photoinduced electron transfer for pyrenesulfonamide conjugates of tryptophan-containing peptides. Mitigation of fluoroprobe behavior in N-terminal labeling experiments

The (nitro)pyrenesulfonamide group has been attached to the N-terminus of tryptophan and tryptophan-containing peptides. Intramolecular electron transfer between pyrene and Trp indole side chains, observed by fluorescence quenching and laser flash photolysis, depends on the spacing between Pyr and Trp moieties and the strength of the electron acceptor.