Two iron-sulfur proteins from Bacillus polymyxa (ferredoxins I and II) have been shown to transfer 1 electron per 4 iron atoms at a potential of -380 and -420 mv, respectively, at pH 7. The proteins contain 4 iron and 4 labile sulfur atoms and 4 cysteine residues in molecules of about 9,000 daltons; electron paramagnetic resonance and optical properties suggest that each contains an iron-sulfur...

Sulfite oxidase (EC 1.8.3.1), when reduced by sulfite, exhibited the electron paramagnetic resonance spectrum of molybdenum(V). Specific calorimetric analyses demonstrated that the purified enzyme contained 1 molybdenum per heme. The electron paramagnetic resonance signal of molybdenum, which was generated by the addition of sulfite, was enriched by the purification procedure to the same degree...

This work is devoted to a study of the structural changes in a single crystal of ammonium nitrate, NH4NO3, doped with copper(II) cations by electron paramagnetic resonance. Ammonium nitrate crystallizes at atmospheric pressure in several polymorphic forms, phase VII → V → IV → III → II → I → melt, with transition temperatures of 103 K, 255 K, 305 K, 357 K, 398 K, and 443 K, respectively. The ai...

DETC: diethyldithiocarbamate, DMPO: 5,5-dimethyl-1-pyrroline N-oxide, DNIC: di-nitrosyl-iron complex, DTCS: N-(dithiocarboxy)sarcosine, EDRF: endothelium-derived relaxing factor, EPR, ESR: electron paramagnetic resonance; electron spin resonance, cGMP: cyclic GMP, Hb: hemoglobin, LPS: lipopolysaccharide, Mb: myoglobin, MGD: N-methyl-D-glucamine dithiocarbamate, MNIC: mono-nitrosyl-iron complex,...

The role of enzyme engineering in biotechnology, biological and pharmaceutical process cannot be over emphasized. This study compared the adsorption of amylase and protease on to manganese ferrite (MnFe2O4). The metal ferrite was synthesized via a sol – gel technique and characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD), Electron paramagnet...

The electronic structure of manganese (Mn) cluster in photosystem II was investigated by electron paramagnetic resonance (EPR) spectroscopy. In order to determine the spin density distribution in magnetically coupled Mn in the S2 state Mn cluster, pulsed electron-electron double resonance (PELDOR) measurement was performed. The local environment of the Mn cluster was investigated by electron-nu...

Based on solvation studies of polymers, the sum (1:1) of the electron acceptor (AN) and electron donor (DN) values of solvents has been proposed as an alternative polarity scale. To test this, the electron paramagnetic resonance isotropic hyperfine splitting constant, a parameter known to be dependent on the polarity/proticity of the medium, was correlated with the (AN+DN) term using three para...

The electronic spin associated with the nitrogen-vacancy (NV) centre in diamond interacts with an environment formed by isotopic impurities and paramagnetic defects; the strength of these interactions depends on the location of each impurity relative to the NV centre. From the electron spin resonance spectra of individual NV centres we infer the possible values and signs of hyperfine splittings...

Electron paramagnetic resonance and electrochemistry are used to evidence the interaction between 1,10-phenanthroline (Phen) and KO(t)Bu to form the 1,10-phenanthroline radical anion, Phen˙(-), and the (t)BuO˙ radical via an inner-sphere electron transfer. In addition, electrochemistry is also used to explain the formation of aryl radicals from aryl bromides via outer-sphere electron transfer f...

According to UV-visible spectroscopy, X-ray diffraction spectrometry, dynamic light scattering, Fourier transform infrared spectroscopy, electron paramagnetic resonance spectroscopy, transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy, nano-sized manganese oxides are proposed as active catalysts for water oxidation in the reaction of some manganes...