EXCITATION-ENERGY TRANSFER BETWEEN TYROSINE AND TRYPTOPHAN IN PROTEINS EVALUATED BY THE SIMULTANEOUS MEASUREMENT OF FLUORESCENCE AND ABSORBANCE |
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Authors: | Yoshio Saito Hideki Tachibana Hidechika Hayashi Akiyoshi Wada |
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Affiliation: | Department of Physics, Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan |
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Abstract: | Abstract— The efficiencies of the excitation–energy transfer from tyrosine to tryptophan residues in eight globular proteins in the native and denatured states are obtained by studying the wavelength dependence of the fluorescence quantum yield. The measurements are made over a wide wavelength range using a computer-controlled spectrophotometer which can measure the fluorescence and absorbance simultaneously in one sample solution (Wada et al. , 1980). The values of the energy transfer efficiencies ranged from 0.17 ± 0.12 to 0.69 ± 0.06 in the native state and from -0.04 ± 0.09 to 0.12 ± 0.06 in the denatured state. These values are considerably lower than the values reported by Kronman and Holmes (1971); in particular, an almost complete absence of energy transfer for the denatured state is shown. |
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