FLUORESCENCE AND THE STRUCTURE OF PROTEIN—XX. FLUORESCENCE OF 3-AMINOTYROSINE AND OTHER AMINOPHENOLS |
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| Authors: | ROBERT W COWGILL |
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| Institution: | Department of Biochemistry, The Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina, U.S.A. |
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| Abstract: | Abstract— –The fluorescence of 3-NH2 tyrosine and of simpler isomeric aminophenols was observed in aqueous solution at room temperature. Marked changes in both emission spectrum and fluorescence efficiency were observed upon change of pH and solvent composition. An explanation for the observed behavior is offered on the basis of two effects. First, peculiarities in the emission spectra were accountable in terms of proton dissociation from the cationic amino group in the excited singlet state so that emission characteristic of the free base was observed even in acidic solutions. Second, the unexpectedly low fluorescence efficiency from the free base was shown to result from quenching by the aqueous solvent. The relevance of these studies for the fluorescence of 3-NH2 tyrosyl groups in proteins is discussed briefly. |
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