EFFECTS OF EXCITED-STATE PROTON TRANSFER ON THE PHOSPHORESCENCE OF TYROSINE-PHOSPHATE COMPLEXES |
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| Authors: | Manfred SchnarrClaude Helene† |
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| Institution: | Centre de Biophysique Moleculaire, C.N.R.S., 1A, Avenue de la Recherche Scientifique, 45045 Orleans Cedex.;Laboratoire de Biophysique, Inserm U 201, Museum National d'Histoire Naturelle, 61, rue Buffon, 75005 Paris, France |
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| Abstract: | Abstract Phosphate anions quench the fluorescence of tyrosine at room temperature as a result of an excited-state proton transfer. At 77 K in frozen solutions the fluorescence of tyrosine is still quenched by phosphate anions but the phosphorescence emission is enhanced. No tyrosinate phosphorescence is detected. A mechanism is proposed to explain these results: excited-state proton transfer from tyrosine to phosphates is followed by intersystem crossing in tyrosinate anions with subsequent back-transfer of the proton in the triplet state. |
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