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'Electron Paramagnetic Resonance' in keywords Facet   section ZfN Section C  [X]
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1Author    Heinz Rupp, K., Jozef Verplaetse, Rene LontieRequires cookie*
 Title    Binuclear Copper Electron Paramagnetic Resonance Signals of a-Methemocyanin of Helix pomatia  
 Abstract    The binuclear electron paramagnetic resonance signals o f a-methemocyanin o f Helix pomatia were investigated at liquid helium temperatures. These signals were completely eliminated by the addition of fluoride and enhanced in the presence o f chloride, which did not alter the saturation behavior. The triplet nature of the signal at g = 4.59 was confirmed by the low power-saturation. The addition of nitrite at pH 5.0 and 0° C yielded slowly and reversibly a seven-line half-field signal. On lowering the temperature the intensity of the triplet signals increased to the lowest tem­ perature reached 4.2 K, excluding a strong exchange coupling. 
  Reference    Z. Naturforsch. 35c, 188—192 (1980); received September 18/November 17 1979 
  Published    1980 
  Keywords    Copper, Electron Paramagnetic Resonance, Hemocyanin, Microwave Power Saturation 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0188.pdf 
 Identifier    ZNC-1980-35c-0188 
 Volume    35 
2Author    R. Om, G., EligiuszS. Erafin, JanuszM. AzurRequires cookie*
 Title    The Kinetics of the Reaction of Thiocyanate and Nitrite Ions with Orconectes limosus Oxyhemocyanin  
 Abstract    The time course of the reaction of oxyhemocyanin from the arthropod Orconectes limosus with SCN" and N 0 2 " was investigated. After addition of one of these anions to oxyhemocyanin solu­ tion an exponential decay of A 340 was found, indicating a removal of oxygen from the active site. The order of reaction with respect to ligand was about 3 for thiocyanate and about 1 for nitrite. On this basis, a possible arrangement of ligands in the active site has been proposed. The final product of reaction with SCN" yielded a mononuclear copper EPR spectrum while the reaction product with N 07 gave a characteristic spectrum of two coupled Cu2+ ions. It was possible to remove the ligands from the active site by dialysis. The reaction patterns showed distinct changes in a narrow pH range, 5.3—6.5. A possible effect of structural alterations of the protein moiety on the course of the reaction of oxyhemocyanin with ligands is suggested. 
  Reference    Z. Naturforsch. 40c, 677—681 (1985); received February 4 1985 
  Published    1985 
  Keywords    Hemocyanin, Reaction Kinetics, Copper, Electron Paramagnetic Resonance 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0677.pdf 
 Identifier    ZNC-1985-40c-0677 
 Volume    40 
3Author    L. Kovács3, U. Hegdeb, S. Padhyeb, G. Bernät3, S. Demeter3Requires cookie*
 Title    Effects of Potassium-(picrate)-(18-crown-6) on the Photosynthetic Electron Transport  
 Abstract    The effects of potassium-(picrate)-(18-crown-6) on the electron transport of photosystem II was investigated in isolated pea thylakoids. Low concentrations of the compound inhibited the fast decay of fluorescence yield associated with electron transfer between the primary (Q a) and secondary (Q b) quinone electron acceptor and increased the intermediary level of fluorescence to the Fmax level. The decay half-time of fluorescence yield measured in the presence of D C M U (S2Q A' charge recombination) decreased from about 1.8 s to about 0.3 s in thylakoids treated with potassium-(picrate)-(18-crown-6). W hile the inhibition of electron transport by D C M U gave rise to the appearance of a thermoluminescence band at about + 10°C (S2Q A~charge recombination) addition of potassium-(picrate)-(18-crown-6) resulted in a thermoluminescence band at about -10°C. Increasing concentrations of potassium-(picrate)-(18-crown-6) diminished the fluorescence yield and the -10°C TL band and abolished the Signal II S and Signal I I f E P R signals of the tyrosine-D and tyrosine-Z electron donors, respec­ tively. The phenolic-type inhibitor, potassium picrate had the same effect on thermolumines­ cence and on the tyrosine E P R signals. It is concluded that potassium-(picrate)-(18-crown-6) is a phenolic type inhibitor owing to its picrate constituent. A t low concentrations picrate and potassium-(picrate)-18-crown) not only block the electron transport between Q A and O b but they probably decrease the midpoint redox potential of Q A, as well. A t high concen­ trations they also inhibit the light-induced oxidation of the tyrosine-D and tyrosine-Z donors. 
  Reference    Z. Naturforsch. 51c, 539—547 (1996); received December 22 1995/ 
  Published    1996 
  Keywords    Phenolic Inhibitors, Photosynthesis, Photosystem II, Thermoluminescence, Electron Paramagnetic Resonance 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0539.pdf 
 Identifier    ZNC-1996-51c-0539 
 Volume    51 
4Author    J. Paul, E. V. Goldammer, H. R. WenzelRequires cookie*
 Title    Pressure Induced Structural Fluctuations in Hemoglobin, Studied by EPR-Spectroscopy  
 Abstract    A quartz based cavity for pressure dependent EPR measurements on liquid samples allowing pressures up to 0.6GPa was constructed. First investigations with this setup were done on spin labeled horse hemoglobin derivatives both in ferric and ferrous state of oxidation. The second derivative EPR spectra show changes of the label's mobility, which are not correlated with spin state changes of the Fe-porphyrin complex, but which point out structural fluctuations inside the globin protein matrices. 
  Reference    Z. Naturforsch. 43c, 162—166 (1988); received December 22 1987 
  Published    1988 
  Keywords    High-Pressure, Electron Paramagnetic Resonance, Second Harmonic Detection, Liquid Systems, Hemo-Proteins, Structural Fluctuation, Ligand Binding 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0162.pdf 
 Identifier    ZNC-1988-43c-0162 
 Volume    43