Mechanism of fluorescence quenching of tyrosine derivatives by amide group

Photophysical Properties of Tyrosine and Its Simple Derivatives in Organic Solvents Studied by Time‐resolved Fluorescence Spectroscopy and Global Analysis¶

“…The different lifetimes of the rotamers arise from the interaction between the phenol fluorophore and the quenching groups. A charge transfer interaction between the excited aromatic chromophore (phenol ring) as a donor and the electrophilic units in the amino acid backbone (the carbonyl of the amide group) as an acceptor was proposed by Cowgill (31,32), Toumon et al (33) and Feitelson (10) and confirmed by others (7,9,24,26). The slow-exchange ground state rotamer model in the case of tyrosine derivatives predicts that the fluorescence intensity decay should be described by the sum of three exponents; this in which the phenol ring comes into the closest contact with the carbonyl group has the shortest fluorescence lifetime.…”

“…For AcTyrNH 2 in all solvents studied monoexponential fluorescence decays were observed, and the fluorescence lifetimes obtained in MeOH and DMSO are comparable to published results (26). For O ‐methyl‐tyrosine and its derivatives with free or with one or both functional groups blocked, the fluorescence decays are mono‐exponential in all studied solvents, whereas in water solution the quenching of Tyr(Me) fluorescence by amide group is observed (7, 9, 15).…”

“…4) and iPrOH are identical (the shape and position) to those of the parent molecule, as in the case of AcTyr in water (15). Also, the fluorescence intensity decay of tyrosine amide in MeOH is heterogeneous, with the second component being much smaller than in water (3, 5, 7, 15), whereas a mono‐exponential decay is observed in isopropanol. Also, for tyrosine amide in methanol, the DAS spectra are identical (the shape and position) to those of the parent molecule (data not shown), as in the case of TyrNH 2 in water (15).…”

Molecular changes in gelatin aging observed by NIR and fluorescence spectroscopy

“…In a lesser extent the decrease of the fluorescence intensity of gelatin spiked with DOPA could be related to the quenching of the fluorescence emission of DOPA standard by the gelatin sample. Indeed, Wiczk et al (2001) observed that DOPA fluorescence was quenched by the amide group by an electron transfer mechanism. The emission peaks of DOPA and gelatin have the same profile, suggesting the presence of DOPA in gelatin.…”

Surfactant and Temperature Effects in Tyrosine/Pyridoxine Hydrochloride Systems

“…Tyrosine is one of the 20 amino acids commonly found in proteins. The photophysical properties of tyrosine and its derivatives are very complex and have been widely investigated [1][2][3][4][5][6]. The fluorescence of aromatic amino acids and their residues incorporated into a peptide or protein chain is the subject of extensive studies because of their use as internal probes in conformational analysis [7][8][9].…”