TY - JOUR AU - Sherin, P.S. AU - Grilj, J. AU - Kopylova, L.V. AU - Yanshole, V.V. AU - Tsentalovich, Y.P. AU - Vauthey, E. TI - Photophysics and Photochemistry of the UV Filter Kynurenine Covalently Attached to Amino Acids and to a Model Protein PY - 2010 JF - Journal of Physical Chemistry B JA - J. Phys. Chem. B SN - 1520-6106 VL - 114 IS - 36 SP - 11909 EP - 11919 L1 - http://pubs.acs.org/doi/pdfplus/10.1021/jp104485k L2 - http://pubs.acs.org/doi/full/10.1021/jp104485k L3 - http://pubs.acs.org/doi/abs/10.1021/jp104485k L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref01080.png M3 - 10.1021/jp104485k UR - http://dx.doi.org/10.1021/jp104485k N2 - The photophysics and photochemistry of kynurenine (KN) covalently bound to the amino acids lysine, cysteine, and histidine, the antioxidant glutathione, and the protein lysozyme have been studied by optical spectroscopy with femto- and nanosecond time resolution. The fluorescence quantum yield of the adducts of KN to amino acids is approximately 2 times higher than that of the free KN in solution; KN attached to protein exhibits a 7-fold increase in the fluorescence quantum yield. The S1 state dynamics of KN-modified lysozyme reveals a multiphasic decay with a broad dispersion of time constants from 1 ps to 2 ns. An increase of the triplet yield of KN bound to lysozyme is also observed; the triplet state undergoes fast intramolecular decay. The obtained results reveal an increase of the photochemical activity of KN after its covalent attachment to amino acids and proteins, which may contribute to the development of oxidative stress in the human lensessthe main causative factor for the cataract onset. ID - 1080 ER -