Electronic processes in the pulse radiolysis of aqueous solutions of halide ions

Khorana, S.; Hamill, William H.

doi:10.1021/j100689a008

Cited by 32 publications

(16 citation statements)

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“…The mean lifetime of highly reactive primary OH' radicals is extremely short. In aqueous NaCl solutions (i.e., in the presence ofCl-ions), part ofOH radicals is converted to secondary C12radicals of considerably longer lifetime (16)(17)(18). As a consequence, the radical-induced modification of polyene molecules seems to proceed with higher efficiency.…”

Section: Resultsmentioning

confidence: 99%

Inactivation by ionizing radiation of ion channels formed by polyene antibiotics amphotericin B and nystatin in lipid membranes: an inverse dose-rate behavior

Barth¹,

Stark²,

Wilhelm³

1993

Biophysical Journal

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The phenomena reported are part of a study about the effects of ionizing radiation on membrane transport. We found that the conductance of lipid membranes in the presence of the polyene-antibiotics nystatin or amphotericin B is reduced to virtually zero following irradiation. Ion channels formed by these substances seem to represent extremely sensitive structures being inactivated by radiation doses in the range of a few Centigray (1 cGy = 1 rad) at sufficiently small dose rates. Inactivation shows a so-called inverse dose-rate behavior, i.e., at constant radiation dose the effect increases with decreasing dose rate. Similar to radiation-induced lipid peroxidation the phenomenon may be understood on the basis of a radical chain mechanism initiated by free radicals of water radiolysis. The process--via peroxidation of the polyene part of the molecules--is suggested to modify the hydrophobic exterior and to destabilize the barrel-like structure of the ion channels.

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Section: Resultsmentioning

confidence: 99%

Inactivation by ionizing radiation of ion channels formed by polyene antibiotics amphotericin B and nystatin in lipid membranes: an inverse dose-rate behavior

Barth¹,

Stark²,

Wilhelm³

1993

Biophysical Journal

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“…Halide ion irradiation was examined using pulse radiolysis by Khorana and Hamill (1971), including iodide and bromide ions. LiCl radiolysis was investigated using pulse radiolysis by Woods et al (1975) in concentrated solutions up to 14 molar.…”

Section: Simple Chemical Systemsmentioning

confidence: 99%

Level 4 Milestone (M4): M41UF033201 - Review of Radiolysis of Brines on the Surface of a Waste Package

Sutton

2011

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“…latter are formed in NaCl or NaBr solutions respectively (Anbar and Thomas 1964, Khorana and Hamill 1971, Jayson et al 1973) . D 37 dose was found to be smaller in NaBr solutions compared with NaCl solutions ( Figure 3, curves 3 and 4) .…”

Section: 1 Evidence For Free Radical-mediated Channel Inactivationmentioning

confidence: 99%

Radiation-induced and Free Radical-mediated Inactivation of Ion Channels Formed by the Polyene Antibiotic Amphotericin B in Lipid Membranes: Effect of Radical Scavengers and Single-channel Analysis

Zeidler

Barth

Stark

1995

International Journal of Radiation Biology

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This paper is part of a study on the effect of ionizing radiation on ion channels in biological membranes. Ion channels formed by polyene antibiotics amphotericin B or nystatin represent clusters of conjugated double bonds. As a consequence of this structural peculiarity, the conductance of lipid membranes--in the presence of polyene channels--has been found to decrease by several orders of magnitude at comparatively small doses of ionizing radiation. The phenomenon shows an inverse dose-rate behaviour similar to that of radiation-induced lipid peroxidation. We report on experiments performed in the presence of various radical scavengers, at varying cholesterol concentrations, and with different lipids. They support the view that channel inactivation is due to free radical-induced peroxidation of the polyenes leading to a destabilization of the barrel-like structure of the ion channels. Radiation-induced channel closing is shown for the first time at the level of single-ion channels.

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Electronic processes in the pulse radiolysis of aqueous solutions of halide ions

Cited by 32 publications

References 1 publication

Inactivation by ionizing radiation of ion channels formed by polyene antibiotics amphotericin B and nystatin in lipid membranes: an inverse dose-rate behavior

Inactivation by ionizing radiation of ion channels formed by polyene antibiotics amphotericin B and nystatin in lipid membranes: an inverse dose-rate behavior

Level 4 Milestone (M4): M41UF033201 - Review of Radiolysis of Brines on the Surface of a Waste Package

Radiation-induced and Free Radical-mediated Inactivation of Ion Channels Formed by the Polyene Antibiotic Amphotericin B in Lipid Membranes: Effect of Radical Scavengers and Single-channel Analysis

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