Quenching of Excited Triplet Lumiflavin by Lumiflavin Radicals Formed in Its T‐t Reaction

Yoshimura, Akio; Ohno, Takeshi

doi:10.1111/j.1751-1097.1991.tb03920.x

Cited by 12 publications

(10 citation statements)

References 26 publications

(31 reference statements)

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“…Even though the kinetic traces obtained in Figure 3b were obtained using the lowest possible power of the pump beam, it is possible that the lifetimes are affected by the bimolecular annihilation processes. 26 The shortening of the triplet excited-state lifetime in I-Fl is consistent with the heavy atom effect caused by the iodo-substituent: the spinorbit interaction in I-Fl causes not only an increase in the rate of S 1 → T 1 intersystem crossing ( Figure 2b), but also leads to increased rate of the T 1 → S 0 relaxation pathway (Figure 3b).…”

Section: Resultssupporting

confidence: 70%

Improved Flavin-Based Catalytic Photooxidation of Alcohols through Intersystem Crossing Rate Enhancement

et al. 2016

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The triplet excited-state formation efficiency in a flavin derivative was increased by the introduction of iodine into the molecular framework. The transient absorption measurements showed that the intersystem crossing rate was 1.1 × 10(10) s(-1), significantly faster than in the parent flavin compound. Furthermore, the photocatalytic efficiency of iodoflavin was evaluated using the oxidation of benzyl alcohol as a model reaction. The benzaldehyde product yields were higher when iodoflavin was used as a photocatalyst, showing that the increased triplet yield directly translates into improved photocatalysis. The iodoflavin catalyst also allowed the use of higher substrate concentrations (since the undesired electron transfer from singlet excited state was minimized), which is expected to improve the practical aspects of photocatalysis by flavins.

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Section: Resultssupporting

confidence: 70%

Improved Flavin-Based Catalytic Photooxidation of Alcohols through Intersystem Crossing Rate Enhancement

et al. 2016

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“…Fritz et al 22 determined a limiting rate constant at low laser energy for the ground state quenching of 1.2 Â 10 8 M À1 s À1 for both lumiflavin and FMN. However, rate constants reported for ground-state quenching as well as triplet-triplet annihilation 22,27,28 have been questioned by Yoshimura and Ohno 29 due to an oversimplification of the models applied.…”

Section: Introductionmentioning

confidence: 99%

Protonated triplet-excited flavin resolved by step-scan FTIR spectroscopy: implications for photosensory LOV domains

Thöing

Pfeifer

Kakorin

et al. 2013

Phys. Chem. Chem. Phys.

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Among many other functions, flavin serves as a chromophore in LOV (light-, oxygen-, or voltage-sensitive) domains of blue light sensors. These sensors regulate central responses in many organisms such as the growth of plants towards light. The triplet-excited state of flavin ((3)Fl) has been identified as a key intermediate in the photocycle of LOV domains, either in its neutral or protonated state. Even time-resolved infrared spectroscopy could not resolve unambiguously whether (3)Fl becomes protonated during the photoreaction, because the protonated triplet-excited state (3)FlH(+) has not been characterized before. Here, the step-scan Fourier transform infrared (FTIR) technique was applied to the flavin mononucleotide (FMN) in aqueous solution at different pH values to resolve laser-induced changes in the time range from 1.5 μs to 860 μs. A high-pressure-resistant flow cell system was established to account for the irreversibility of the photoreaction and the small path length. Several marker bands were identified in the spectrum of (3)Fl in water and assigned by quantum chemical calculations. These bands exhibit a solvent-induced shift as compared with previous spectra of (3)Fl in organic solvents. The marker bands undergo a further distinct shift upon formation of (3)FlH(+). Band patterns can be clearly separated from those of the anion radical or the fully reduced state resolved in the presence of an electron donor. A comparison to spectra of (3)Fl in LOV domains leads to the conclusion that (3)FlH(+) is not formed in the photoreaction of these blue light sensors.

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“…The present newly designed continuous irri gation system showed good results in 6 chem ical burn cases, and this system includes many merits as follow, in comparison with the previ ous systems [1][2][3][4][5]: (1) effectiveness with a little volume of irrigating fluid, (2) low cost of the equipment and (3) simplicity to set up the sys tem. (4) possibility to be irrigated during trans portation from the accident place to the hospi tal without any labors, (5) possibility for the patients to take much rest during washing and to move to a small extent on the bed, (6) keep ing the space between palpebral and bulbal conjunctiva, which prevents Symblepharon, (7) uniform irrigation in the conjunctival sac because of the high pressure of fluid by the Primary irrigation indicates irrigation at the actual spot; severity according to Roper-Hall's classification [6]; D = right eye; S = left eye.…”

Section: Discussionmentioning

confidence: 99%

“…Sometimes, doctors or nurses have to wash their eyes continuously for hours. Although some irrigating systems have been applied to cases of chemical burns [1][2][3][4][5], these had in cluded many problems, e.g. low effectiveness available in any clinics by materials such as a tube for infants.…”

Section: Introductionmentioning

confidence: 99%

Newly Designed Continuous Corneal Irrigation System for Chemical Burns

Yamabayashi¹,

Furuya²,

Gohd³

et al. 1990

Ophthalmologica

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A newly designed continuous irrigation system has been applied in our clinic. Six cases of corneal chemical burns have been treated with this system from September 1988 to February 1989. The present system has been available in any clinics by materials such as a disposable intravenous tube and a scalp vein tube for infants. Compared with the methods previously reported, this system showed good results, simplicity for setting up, good patient tolerance and low cost of the equipment.

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Quenching of Excited Triplet Lumiflavin by Lumiflavin Radicals Formed in Its T‐t Reaction

Cited by 12 publications

References 26 publications

Improved Flavin-Based Catalytic Photooxidation of Alcohols through Intersystem Crossing Rate Enhancement

Improved Flavin-Based Catalytic Photooxidation of Alcohols through Intersystem Crossing Rate Enhancement

Protonated triplet-excited flavin resolved by step-scan FTIR spectroscopy: implications for photosensory LOV domains

Newly Designed Continuous Corneal Irrigation System for Chemical Burns

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