Electronic Spectrum of Photo-Induced Transients in Solutions of Tryptophan at 77°K

Hase, Hirotomo; Higashimura, Takenobu; Sidei, Tunahiko

doi:10.1143/jpsj.23.658

Cited by 9 publications

(2 citation statements)

References 2 publications

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“…This may be inferred from the ESR data of Pailthorpe and Nicholls,30 as well as from the optical absorption spectra of Hase et al ,32 which are analogous to our data for EG/HzO (Fig. The spectra show that there is a net loss of radicals in this process.…”

Section: A Oxidized Speciessupporting

confidence: 89%

Ultraviolet- and x-ray-induced radicals in frozen polar solutions of L-tryptophan

Moan

Kaalhus

1974

The Journal of Chemical Physics

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Section: A Oxidized Speciessupporting

confidence: 89%

Ultraviolet- and x-ray-induced radicals in frozen polar solutions of L-tryptophan

Moan

Kaalhus

1974

The Journal of Chemical Physics

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“…Armstrong and Swallow [42] proposed that hydroxyl ions react with photo-oxidized tryptophan in rigid media, to explain why the spectrum obtained by U.V. irradiation at 77°K [43] is so similar to the O H radical adduct. The reaction can be represented as:…”

Section: H Hmentioning

confidence: 99%

Flash Photolysis and Inactivation of Aqueous Lysozyme*

Grossweiner

Usui

1971

Photochem & Photobiology

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Flash photolysis of aqueous lysozyme has shown that the initial photochemical products are photo-oxidized tryptophan residues ( A , , , = 500 nm), hydrated electrons (Amax = 720 nm), and the cystine residue electron adduct ( A , , , = 420 nm). Comparisons with mixtures of the chromophoric amino acids show that 1 to 2 tryptophan residues provide electrons at a quantum yield of 0.018 (25 per cent). Part of the ejected electrons are captured by cystine residues via a short-range, intramolecular process with essentially unit efficiency. The remainder become hydrated and back react with oxidized tryptophan residues before sec. The cystine residue electron adduct decays with 2 msec halftime (25°C) and 1.5 kcal/mole activation energy. The surviving oxidized tryptophan residues decay with a comparable time constant in a hydroxyl ion catalyzed process. In acid solutions the oxidized tryptophan residue and long-lived H atom adduct are observed (A,,, = 380 nm). The quantum yield of lysozyme inactivation induced by xenon Rash irradiation above 250 nm is 0.023 (20 per cent), which is not sensitive to oxygen or pH. Comparison to the primary photochemical reactions indicates that electron ejection from the essential tryptophan residues inactivates the enzyme, irrespective of the electron trap and subsequent reactions. On the basis of the structure and supporting information it is proposed that the tryptophan residues of the active site are involved. Direct disruption of cystine residues does not contribute more than 10 per cent to the inactivation quantum yield in this wavelength region. Lysozyme inactivation may differ from other enzymes because the chromophores include essential residues located in the active center.

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Trapped Electrons in Rigid Polar solution. A Study of Recombination Luminescence

Moan¹

1971

Ber Bunsenges Phys Chem

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The afterglow (A) and thermoluminescence (TL) of tryptophan in ethyleneglycol/water‐glass irradiated with 250 nm UV‐light at 77°K have been studied. Both A and TL are attributed to recombination between tryptophan ions and trapped electrons produced by ionization of tryptophan by triplet absorption. The excitation energy of the molecule formed by the recombination is between 3.0 and 4.0 eV. The intensity I of A decays according to I = const t−1.09. The glow curve has two peaks: TL1 at 90°K and TL2 at 135°K. TL2 is associated with a glass transition of the solvent and occurs in the same temperature region as the optical absorption from the trapped electron disappears. The effect of electron scavengers on the thermoluminescence shows that the glow curve may be interpreted in terms of the distance be the trapped electron and the positive ion. A and TL1 is associated with electrons that are trapped fairly close to their mother ions whose recombination is guided by the Coulomb force. The electrons associated with TL2 are trapped at larger distances but probably so large as the mean trapping distance. As judged from scavenging experiments a lower limit of the mean trapping distance is 20 Å. On their way back to the mother ions the electrons do not behave like “thermal” but rather like solvated ones with respect to reactivity with H. The yield of trapped electrons increases and the electrons also seem to be trapped closer to their mother ions when the irradiation temperature increases. This may be caused by increased mobility of the molecular dipoles or OH‐groups and/or by the higher thermal energy of the electrons prior to trapping.

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Electronic Spectrum of Photo-Induced Transients in Solutions of Tryptophan at 77°K

Cited by 9 publications

References 2 publications

Ultraviolet- and x-ray-induced radicals in frozen polar solutions of L-tryptophan

Ultraviolet- and x-ray-induced radicals in frozen polar solutions of L-tryptophan

Flash Photolysis and Inactivation of Aqueous Lysozyme*

Trapped Electrons in Rigid Polar solution. A Study of Recombination Luminescence

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