Paramagnetic anisotropy measurements on acid ferrimyoglobin and ferrimyoglobin fluoride

Uenoyama, Harumi; Iizuka, Tetsutarō; Morimoto, Hideki; Kotani, Masao

doi:10.1016/0005-2795(68)90082-2

Cited by 33 publications

(2 citation statements)

References 7 publications

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“…The data have not been offset, but it is the relative slopes at a given temperature that are of primary interest rather than the actual susceptibility values. The slope of the experimental data curve falls between the slopes of the theoretical curves calculated by using D values of 3 and 10 cm"1, a range typical of that found for other heme proteins (Tasaki et al, 1966;Uenoyama et al, 1968; Behere et al, 1979). This indicates that a reasonable value of the zero-field splitting parameter is sufficient to explain the deviation from the Curie Law at low temperatures for the resting enzyme.…”

Section: Resultssupporting

confidence: 73%

Magnetic state of the a3 center of cytochrome c oxidase and some of its derivatives

Barnes

Babcock²,

Dye³

1991

Biochemistry

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The temperature dependence of the magnetic susceptibility was used to investigate the nature of the coupling between cytochrome alpha 3 and CuB in resting and oxidized cyanide- and formate-bound cytochrome oxidase. Resting and formate-bound enzymes were found to have strong antiferromagnetic coupling with an S = 5/2 cytochrome alpha 3, results that were independent of the dispersing detergent and the enzyme isolation method. The cyanide-bound enzyme was heterogeneous, with a minor fraction showing intermediate strength antiferromagnetic coupling. The magnitude of this coupling was independent of the enzyme isolation method and depended moderately on the identity of the dispersing detergent. The major fraction of the cyanide-bound enzyme had a lowest energy state of Ms = 0. The coupling constant for this fraction did not depend on the isolation technique or on the identity of the dispersing detergent. The use of glucose-glucose oxidase to deoxygenate samples influenced the susceptibility behavior of some preparations of both the resting and formate-bound enzymes, with results indicating an S = 3/2 cytochrome alpha 3 in the resting enzyme samples. Retention of a 417-nm Soret band for formate-bound enzyme concomitant with peroxide-induced changes in susceptibility behavior indicates different sites of enzyme interactions for the formate ion and hydrogen peroxide.

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Section: Resultssupporting

confidence: 73%

Magnetic state of the a3 center of cytochrome c oxidase and some of its derivatives

Barnes

Babcock²,

Dye³

1991

Biochemistry

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“…Susceptibility D ~ 7 cm -1 D ~ 10 cm -1 [33] Mössbauer D ~ 7 cm -1 , g = 2.0 [34,35] Torque D ~ 12 cm -1 [36] Torque D = 6.5(24) cm -1 D = 10.5(5) cm -1 [37] MF EPR (10,35 and 70 GHz) D = 7.0(5) cm -1 , E = 0.021 (7) First studies in the ZFS of metMb and metHb with fluoro and aquo ligands were based on torque [36], Mössbauer [34,35] and susceptibility [33] measurements. These pioneering studies provided important estimates of D. Subsequent torque measurement on metMb and metMb(F) addressed the temperature dependence of D [37]. However, it was found that D-values spread out over several wavenumbers for different temperatures and crystal orientations.…”

Section: Discussionmentioning

confidence: 99%

Zero-field splittings in metHb and metMb with aquo and fluoro ligands: a FD-FT THz-EPR study

et al. 2013

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Disclaimer: The publisher's version overrides in case of any discrepancy.Combined X-band and Frequency-Domain Fourier-Transform THz-EPR (FD-FT THz-EPR) has been employed to determine heme Fe(III) S = 5/2 zero field splitting (ZFS) parameters of frozen solution metHb and metMb, both with fluoro and aquo ligands. Frequency domain EPR measurements have been carried out by an improved synchrotron based FD-FT THz-EPR spectrometer. ZFS has been determined by the field dependence of spin transitions within the mS=±1/2 manifold, for all four protein systems, and by zero field spin transitions between mS = ±1/2 and mS = ±3/2 levels, for metHb and metMb flouro-states. FD-FT THz-EPR data were simulated with a novel numerical routine based on Easyspin, which allows now for direct comparison of EPR spectra in field and frequency domain.We found purely axial zero field splittings of: D = 5.0(1) cm -1 (flouro-metMb), D = 9.2(4) cm -1 (aquo-metMb), D = 5.1(1) cm -1 (flouro-metHB) and D = 10.4(2) cm -1 (aquo-metHb).

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Chemical Applications of Magnetic Anisotropy Studies on Transition Metal Complexes

Mitra¹

1977

Progress in Inorganic Chemistry

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Paramagnetic anisotropy measurements on acid ferrimyoglobin and ferrimyoglobin fluoride

Cited by 33 publications

References 7 publications

Magnetic state of the a3 center of cytochrome c oxidase and some of its derivatives

Magnetic state of the a3 center of cytochrome c oxidase and some of its derivatives

Zero-field splittings in metHb and metMb with aquo and fluoro ligands: a FD-FT THz-EPR study

Chemical Applications of Magnetic Anisotropy Studies on Transition Metal Complexes

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