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QUENCHING OF CHEMICALLY and ENZYMICALLY‐GENERATED TRIPLET ACETONE BY TYROSINE and 3,5‐DIHALOGENODERIVATIVES
Author(s) -
RivasSuárez Edy,
Catalani Luiz H.,
J. Etelvino,
Bechara H,
Cilento Giuseppe
Publication year - 1983
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1983.tb04439.x
Subject(s) - quenching (fluorescence) , chemistry , acetone , phosphorescence , photochemistry , excited state , triplet state , fluorescence , organic chemistry , molecule , physics , quantum mechanics , nuclear physics
Tyrosine and especially its 3,5‐dihalogenoderivatives quench acetone triplets. When the excited acetone is generated free in solution, the Stern‐Volmer plots for the quenching by these species, monitored via the sensitized emission of the 9,10‐dibromoanthracene‐2‐sulfonate ion, are linear. When triplet acetone is generated enzymically by the peroxidase‐catalyzed aerobic oxidation of isobutyral‐dehyde, the Stern‐Volmer plots for the quenching of the acetone phosphorescence curve upwards in the case of 3,5‐dibromotyrosine and even more markedly with 3,5‐diiodotyrosine. Quenching appears likely to occur by triplet‐triplet energy transfer and especially in the case of the phenoxide form, also by electron transfer. The curvature denotes a static contribution to quenching favoured by the enzyme.