Spectroscopic Properties of Isolated Protein Chromophores

Absorption and emission of proteins in the near-UV region is due, first of all, to tryptophan, tyrosine, and phenylalanine residues, which are natural reporter groups in protein molecules (Figure 1). Interpretation of fluorescence spectra of proteins requires knowledge of spectroscopic properties of these amino acids in the isolated state. ¹ , ^{4 , 5 , 6 , 7}