Fluorescence and Phosphorescence of Wool Keratin Excited by UV-A Radiation

Corrected fluorescence and phosphorescence spectra of wool keratin excited by UV-A radiation are presented. Some of the observed luminescence is believed to originate from N-formylkynurenine residues, which are photo-oxidation products of tryptophan residues. The positions of the spectral maxima of the fluorescence and phosphorescence arising from N-formylkynurenine residues indicate that there is hydrogen bonding between the ortho carbonyl group of N-formylkynurenine and the N-H group of a protein peptide linkage. The N-formylkynureninine residues also appear to be located principally in regions of low polarity.