The labelling of peptides and proteins with a new fluorophore: N-acetyl-DL-(p-N',N'-dimethylamino)phenylalanine.

It was found that N-acetyl-DL-(p-N',N'-dimethylamino)phenylalanine, in the form of azlactone, can be introduced into a peptide or protein molecule as a new convenient fluorescent marker. A fluorophore of similar properties: N-acetyl-(p-amino)phenylalanine can be introduced into a peptide chain by the reaction with the azlactone of N-acetyl-(p-nitro)phenylalanine followed by reduction of nitro group to amino group. This method, however, cannot be applied to proteins.