ABSTRACT
Aromatic amino acid content and identification in peptides is particularly useful in protein digest applications where a known protein sequence is fragmented and certain predicted fragments can be identified solely by their UV spectral data. The advent of ultraviolet-visible diode-array detection systems in high-performance liquid chromatography has made the real time spectral analysis of peptide components a practical and useful tool to the peptide chromatographer. The acquisition of spectra at the apex and on the upslope and downslope of each peak can yield valuable information concerning peak purity. The assignment of the aromatic amino residues in the peptide is complicated since the spectra of the three (phenylalanine, tyrosine and tryptophan) aromatic amino acid residues overlap. Derivatives of the second order are normally used in preference to higher orders of derivatization since they represent a compromise between selectivity and interference from false absorptions.
