Magnetic Field Effect in the Reaction of Recombination of Nitric Oxide and Superoxide Anion

Karogodina, Tatiana Y.; Sergeeva, Svetlana V.; Stass, Dmitri V.

doi:10.1007/s00723-009-0018-2

Cited by 14 publications

(13 citation statements)

References 61 publications

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“…Biologically relevant radicals with no or very few hydrogen and nitrogen atoms near the unpaired electron are scarce. Superoxide, 2 O  , is one and nitric oxide, NO  , is another but both have such fast spin relaxation (probably ~1 ns (64,65)) that they can be excluded (66). The only other radical discussed in the context of magnetoreception is that formed by oxidation of ascorbic acid, Asc  .…”

Section: Assumptions and Approximationsmentioning

confidence: 99%

Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

Hore

2018

Preprint

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Prolonged exposure to weak (~1 T) extremely-low-frequency (ELF, 50/60 Hz) magnetic fields has been associated with an increased risk of childhood leukaemia. One of the few biophysical mechanisms that might account for this link involves short-lived chemical reaction intermediates known as radical pairs. In this report, we use spin dynamics simulations to derive an upper bound of 10 parts per million on the effect of a 1 T ELF magnetic field on the yield of a radical pair reaction. By comparing this figure with the corresponding effects of changes in the strength of the Earth's magnetic field, we conclude that if exposure to such weak 50/60 Hz magnetic fields has any effect on human biology, and results from a radical pair mechanism, then the risk should be no greater than travelling a few kilometres towards or away from the geomagnetic north or south pole.

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Section: Assumptions and Approximationsmentioning

confidence: 99%

Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

Hore

2018

Preprint

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“…So the system of differential equations was integrated numerically in order to determine Y as a function of k 2) The sink channels for NO and O 2 C À are assumed to be both of second-order kinetics with the following rate equations [Eqs. (30) and (31)]:…”

Section: Modeling the Mfe On The Product Yieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…[28][29] To the best of our knowledge, the only statistically reliable MFE on a product yield was reported in a single field of 4.7 T for an in vitro model system mimicking biological in situ generation of ONOO À by recombination of NO and O 2 C À and irreversible oxidation of a substrate by ONOO À . [30] The overall reaction system starting with the formation of NO and O 2 C À by thermal decomposition of 3-(4-morpholino)sydnonimine (SIN-1) in aerated solution is rather complex. In this work, we characterize in more detail the kinetic sequence leading to the final oxidation product rhodamine 123 (RH) formed by oxidation of of dihydrorhodamine 123 (DHR) via the intermediate ONOO À , and explore the magnetic-field dependence of the effect in a field range up to 18 T. Based on the experimental findings we develop a theoretical framework accounting for the MFE in terms of the spin chemistry of the NO/O 2 C À radical pair.…”

Section: Introductionmentioning

confidence: 99%

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Kinetic Magnetic‐Field Effect Involving the Small Biologically Relevant Inorganic Radicals NO and O₂^.−

et al. 2011

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Oxidation of dihydrorhodamine 123 (DHR) to rhodamine 123 (RH) by oxoperoxonitrite (ONOO(-)), formed through recombination of NO and O(2)(·-) radicals resulting from thermal decomposition of 3-morpholinosydnonimine (SIN-1) in buffered aerated aqueous solution at pH 7.6, represents a kinetic model system of the reactivity of NO and O(2)(·-) in biochemical systems. A magnetic-field effect (MFE) on the yield of RH detected in this system is explored in the full range of fields between 0 and 18 T. It is found to increase in a nearly linear fashion up to a value of 5.5±1.6 % at 18 T and 23 °C (3.1±0.7 % at 40 °C). A theoretical framework to analyze the MFE in terms of the magnetic-field-enhanced recombination rate constant k(rec) of NO and O(2)(·-) due to magnetic mixing of T(0) and S spin states of the radical pair by the Δg mechanism is developed, including estimation of magnetic properties (g tensor and spin relaxation times) of NO and O(2)(·-) in aqueous solution, and calculation of the MFE on k(rec) using the theoretical formalism of Gorelik at al. The factor with which the MFE on k(rec) is translated to the MFE on the yield of ONOO(-) and RH is derived for various kinetic scenarios representing possible sink channels for NO and O(2)(·-). With reasonable assumptions for the values of some unknown kinetic parameters, the theoretical predictions account well for the observed MFE.

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“…Moreover, O 2 is biologically ubiquitous and an FADsuperoxide radical pair could arise during the dark oxidation of fully reduced FAD: [40]. However, the strong spin-orbit coupling in O †À 2 [41], and the zero-field splitting in O 2 [42], almost certainly lead to extremely fast (less than 1 ns) electron spin relaxation [23,43,44] which would preclude any significant response to a 50 mT magnetic field. The only way in which O †À 2 might relax sufficiently slowly would be if it were strongly and asymmetrically bound to cryptochrome so that its orbital angular momentum was quenched [23].…”

Section: [Fadmentioning

confidence: 99%

Alternative radical pairs for cryptochrome-based magnetoreception

Lee

Lau

Hogben

et al. 2014

J. R. Soc. Interface.

126

256

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There is growing evidence that the remarkable ability of animals, in particular birds, to sense the direction of the Earth's magnetic field relies on magnetically sensitive photochemical reactions of the protein cryptochrome. It is generally assumed that the magnetic field acts on the radical pair [formed by the transfer of an electron from a group of three tryptophan residues to the photo-excited flavin adenine dinucleotide cofactor within the protein. ] arise from the asymmetric distribution of hyperfine interactions among the two radicals and the near-optimal magnetic properties of the flavin radical. We close by discussing the identity of Z † and possible routes for its formation as part of a spin-correlated radical pair with an FAD radical in cryptochrome.

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Magnetic Field Effect in the Reaction of Recombination of Nitric Oxide and Superoxide Anion

Cited by 14 publications

References 61 publications

Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

Kinetic Magnetic‐Field Effect Involving the Small Biologically Relevant Inorganic Radicals NO and O₂^.−

Alternative radical pairs for cryptochrome-based magnetoreception

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Magnetic Field Effect in the Reaction of Recombination of Nitric Oxide and Superoxide Anion

Cited by 14 publications

References 61 publications

Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

Kinetic Magnetic‐Field Effect Involving the Small Biologically Relevant Inorganic Radicals NO and O2.−

Alternative radical pairs for cryptochrome-based magnetoreception

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Kinetic Magnetic‐Field Effect Involving the Small Biologically Relevant Inorganic Radicals NO and O₂^.−