TY - JOUR

T1 - Photophysics and photochemistry of the UV filter kynurenine covalently attached to amino acids and to a model protein

AU - Sherin, Peter S.

AU - Grilj, Jakob

AU - Kopylova, Lyudmila V.

AU - Yanshole, Vadim V.

AU - Tsentalovich, Yuri P.

AU - Vauthey, Eric

N1 - This work was supported by the following agencies: FASI state contracts 02.512.11.2278, 02.740.11.0262, and P708, Russian Foundation for Basic Research (projects 08-03-00539 and 09-04-12135), Grant of the President of Russian Federation (grant NSh-7643.2010.3), the Division of Chemistry and Material Science, Russian Academy of Sciences, the SNF (Project Nr. 200020-124393), and the University of Geneva. P.S.S. thanks the European Scientific Foundation (DYNA Exchange Grant #1929).

PY - 2010/9/16

Y1 - 2010/9/16

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 lenses-the main causative factor for the cataract onset.

AB - 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 lenses-the main causative factor for the cataract onset.

UR - http://www.scopus.com/inward/record.url?scp=77956539375&partnerID=8YFLogxK

U2 - 10.1021/jp104485k

DO - 10.1021/jp104485k

M3 - Article

AN - SCOPUS:77956539375

VL - 114

SP - 11909

EP - 11919

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

IS - 36

ER -