ChemInform Abstract: NATURE, IDENTIFICATION, AND PROPERTIES OF INTERMEDIATES PRODUCED BY UV EXCITATION OF INDOLE DERIVATIVES AT LOW AND ROOM TEMPERATURES. SOME APPLICATIONS TO TRYPTOPHAN‐CONTAINING PROTEINS

Santús, René; Bazin, M.; Aubailly, M.

doi:10.1002/chin.198114358

Cited by 12 publications

(28 citation statements)

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“…The fluorescence band of indole derivatives is solvent dependent, being less structurated and red shifted in polar solvents (De Lauder and Wahl, 1971;Tatischeff et al, 1978;Santus et al, 1980). These characteristics have been extensively employed to infer the indole moiety microenvironment (Turro et af., 1980, Encinas andLissi, 1985;Lissi et al, 1990).…”

Section: Fluorescence Band Position and Lifetimesmentioning

confidence: 99%

PHOTOPHYSICAL STUDIES OF INDOLE ALKANOIC ACIDS and TRYPTAMINE IN REVERSE MICELLES OF SODIUM DIOCTYL SULFOSUCCINATE

Encinas

Lissi

Bertolotti

et al. 1990

Photochem & Photobiology

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Abstract— The fluorescence spectra and emission lifetimes of several 3‐alkanoic indoles of different chain length and tryptamine (TA) were studied in sodium dioctyl sulfosuccinate (AOT)/heptane reverse micelles over a wide range of water/AOT ratio (R ‐ 5 to 44). Fluorescence quenching experiments were done using carbon tetrachloride and acrylamide as quenchers. Experiments with TA were carried out using water at pH 3 in order to assure its protonation. Under these conditions, the results indicate that the indole moiety of TA remains at the micellar interface over all the range considered. Furthermore, the results can be interpreted assuming for the TA population a single microenvironment whose properties remain almost invariant when R increases from 11 to 44. The studies employing the 3‐alkanoic indoles were carried out at pH 10. Under these conditions, the anions are progressively displaced to the water pool when the R value increases. This displacement is determined by the length of the side alkyl chain of the 3‐indole derivatives. For these compounds, the quenching experiments indicate that, even at low R values, the excited indole moieties are distributed among different microenvironments.

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Section: Fluorescence Band Position and Lifetimesmentioning

confidence: 99%

PHOTOPHYSICAL STUDIES OF INDOLE ALKANOIC ACIDS and TRYPTAMINE IN REVERSE MICELLES OF SODIUM DIOCTYL SULFOSUCCINATE

Encinas

Lissi

Bertolotti

et al. 1990

Photochem & Photobiology

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“…An alternative method is to compare the fluorescence‐normalized yield, φ T /φ F , among indole derivatives and proteins that exhibit long‐lived phosphorescence, assuming that photochemistry does not contribute to the long‐lived protein emission. In the case population of T 1 by photochemistry is negligible, the ratio φ T /φ F =φ isc /φ F = k isc / k F (intersystem crossing to radiative fluorescence rate) is expected to be largely independent of indole derivative, solvent and temperature conditions ( 28–30 ).…”

Section: Resultsmentioning

confidence: 99%

“…Last, the change of solvent from water to propylene glycol (PG), which decreases φ e ( 28 ), had no significant effect on the P 0 /F ratio of NATA.…”

Section: Resultsmentioning

confidence: 99%

“…The survival of both the free electron and the radical cation are strongly influenced by the solution pH. The proton is an efficient electron scavenger ( 31,32 ) ( k H+ = 2.3 × 10 10 M −1 s −1 ) whereas hydrogen abstraction from the cation radical at neutral‐alkaline pH leads to the formation of the neutral radical in about 1 μs ( 21,28 ). The phosphorescence lifetime of indole and NATA was found to be constant in neutral‐alkaline solutions but decreased sharply at acidic pH.…”

Section: Resultsmentioning

confidence: 99%

“…The indole triplet state exhibits a characteristic reactivity toward O 2 distinct from that of the electron and radical cation pair ( 28,30 ). In flash photolysis studies, the high sensitivity of the triplet state to oxygen quenching ( 21 ) (second‐order rate constant k O 2 = 5 × 10 9 M −1 s −1 ) has been used to suppress T‐T absorption to detect selectively the absorption of other transient photoproducts, such as the radical cation whose half‐life is much less affected by dissolved O 2 ( 21,28 ). Phosphorescence quenching of free indole derivatives by O 2 has never been reported before, presumably because of the difficulty to accurately measure [O 2 ] in the micromolar‐submicromolar range.…”

Section: Resultsmentioning

confidence: 99%

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The Triplet‐state Lifetime of Indole Derivatives in Aqueous Solution^¶

Strambini

Kerwin

Mason

et al. 2004

Photochem & Photobiology

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An important feature of tryptophan phosphorescence, crucial for probing protein structure and dynamics, is the drastic reduction of the lifetime (τ) in fluid solutions. Initial reports of indole and derivatives showed that τ decreases from 6 s in rigid glasses to about 1 ms in aqueous solutions at ambient temperature. Recently a report by Fischer et al. questioned the validity of the millisecond lifetime, claiming that in millimolar electrolyte solutions τ is about 40 μs, similar to the 12–30 μs of earlier determinations based on flash photolysis. Longer lived phosphorescence was detected in pure water but because it exhibited an initial growing phase and an anomalously large triplet yield, the emission was attributed to an artifact arising from the slow, first‐order, geminate recombination of the radical cation and electron generated by photochemistry. In this study, we reexamine both the phosphorescence lifetime and the triplet quantum yield of indole, N‐acetyl tryptophanamide (NATA), N‐methyl tryptophan and the tryptophan‐glycine‐glycine tripeptide under the same conditions adopted by Fischer et al. as well as over a wider range of electrolyte and buffering salts concentrations, pH, solvent and temperture. Throughout, the results show that the phosphorescence decay is slow and uniform down to the 12 μs resolution of the instrument, with no evidence of short‐lived, 40 μs‐like components. Most compelling was the similarity between the fluorescence‐normalized triplet yield of indole derivatives in water and that of W59 in the protein ribonuclease T1 or of NATA in rigid glasses. Its invariance over experimental conditions that varied the production of photoproducts several fold and the characteristic susceptibility of the triplet lifetime to O2, proton and ground state quenching demonstrated that the triplet state was formed predominantly through normal intersystem crossing and that its unquenched lifetime was at least 9 ms.

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Time-resolved and steady-state fluorescence quenching of N-acetyl-l-tryptophanamide by acrylamide and iodide

Zelent

Kuśba

Gryczyński

et al. 1998

Biophysical Chemistry

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We examined the time-resolved and steady-state fluorescence quenching of N-acetyl-L-tryptophanamide (NATA) by acrylamide and iodide, over a range of viscosities in propylene glycol. The quenching of NATA by acrylamide and iodide results in heterogeneity of the intensity decay which increases with the quencher concentration. We attribute the complex decays of NATA to transient effects in diffusion and the nature of the fluorophore-quencher interaction. These data were compared using the phenomenological radiation boundary condition (RBC) and distance-dependent quenching (DDQ) models for collisional quenching. We used global analysis of the time-resolved frequency-domain and steady-state data to select between the models. Consideration of both the frequency-domain and steady state data demonstrate that the quenching rate depends exponentially on the fluorophore-quencher distance, indicating the validity of the DDQ model. The rate constants for acrylamide and iodide quenching, at the constant distance of 5 A, were found to be near 10(13) s-1 and 10(9) s-1, respectively. These rates reflect electron transfer and exchange interactions as the probable quenching mechanisms, respectively.

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ChemInform Abstract: NATURE, IDENTIFICATION, AND PROPERTIES OF INTERMEDIATES PRODUCED BY UV EXCITATION OF INDOLE DERIVATIVES AT LOW AND ROOM TEMPERATURES. SOME APPLICATIONS TO TRYPTOPHAN‐CONTAINING PROTEINS

Cited by 12 publications

References 0 publications

PHOTOPHYSICAL STUDIES OF INDOLE ALKANOIC ACIDS and TRYPTAMINE IN REVERSE MICELLES OF SODIUM DIOCTYL SULFOSUCCINATE

PHOTOPHYSICAL STUDIES OF INDOLE ALKANOIC ACIDS and TRYPTAMINE IN REVERSE MICELLES OF SODIUM DIOCTYL SULFOSUCCINATE

The Triplet‐state Lifetime of Indole Derivatives in Aqueous Solution^¶

Time-resolved and steady-state fluorescence quenching of N-acetyl-l-tryptophanamide by acrylamide and iodide

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ChemInform Abstract: NATURE, IDENTIFICATION, AND PROPERTIES OF INTERMEDIATES PRODUCED BY UV EXCITATION OF INDOLE DERIVATIVES AT LOW AND ROOM TEMPERATURES. SOME APPLICATIONS TO TRYPTOPHAN‐CONTAINING PROTEINS

Cited by 12 publications

References 0 publications

PHOTOPHYSICAL STUDIES OF INDOLE ALKANOIC ACIDS and TRYPTAMINE IN REVERSE MICELLES OF SODIUM DIOCTYL SULFOSUCCINATE

PHOTOPHYSICAL STUDIES OF INDOLE ALKANOIC ACIDS and TRYPTAMINE IN REVERSE MICELLES OF SODIUM DIOCTYL SULFOSUCCINATE

The Triplet‐state Lifetime of Indole Derivatives in Aqueous Solution¶

Time-resolved and steady-state fluorescence quenching of N-acetyl-l-tryptophanamide by acrylamide and iodide

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The Triplet‐state Lifetime of Indole Derivatives in Aqueous Solution^¶