A Novel Acridone Derivative for the Fluorescence Tagging and Mass Spectrometric Sequencing of Peptides.

An acridone derivative containing an activated carboxylic group is highly reactive towards primary amine groups, and allows selective analysis either using absorbance at a wavelength of 410 nm or fluorescence at excitation and emission wavelengths of 400 and 418 nm, respectively; MS–MS analysis of peptides tagged with this reagent gives fragmentation patterns which are usually considerably more intense than background.