| | 1 | Author
| DessislavaN. Ikolova, G. Eo Rg Iev A3, Stanka Stoevab, W. Olfgang, V. Oelterb, NicolayG. Enov | Requires cookie* | | | Title
| Viviparus ater Hemocyanin: Investigation of the Dioxygen-Binding Site and Stability of the Oxy-and Apo-Forms  | | | | Abstract
| The active site of Viviparus ater (mollusc) hemocyanin was investigated using the fact that the binding of dioxygen to the binuclear copper-containing sites of hemocyanins is connected with the appearance of specific dichroic bands which are very sensitive to changes in the structrure and polarity of the environment. O xy-V iviparus ater hemocyanin exhibits near UV and visible circular dichroism spectra different from those of other molluscan and arthropo-dan hemocyanins. These differences are due probably to variations in the geometry or charge distribution in the dioxygen binding sites of the com pared proteins. The thermostability of Viviparus ater hemocyanin and the significance of the copper-dioxy-gen system for the stability were also investigated. "M elting" tem peratures, Tm, of 77 °C for the oxy-hemocyanin and 57 °C for the apo-protein were calculated from the denaturation curves which demonstrates the considerable role of the binuclear active site for the therm o stability. Viviparus ater hemocyanin is more therm ostable than other hemocyanins for which data are published. | | | |
Reference
| Z. Naturforsch. 56c, 843—847 (2001); received A pril 9/May 18 2001 | | | |
Published
| 2001 | | | |
Keywords
| Dioxygen Transport, Hemocyanin, Mollusc | | | |
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| default:Reihe_C/56/ZNC-2001-56c-0843.pdf | | | | Identifier
| ZNC-2001-56c-0843 | | | | Volume
| 56 | |
| 2 | Author
| Heinz Rupp, K., Jozef Verplaetse, Rene Lontie | Requires 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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| default:Reihe_C/35/ZNC-1980-35c-0188.pdf | | | | Identifier
| ZNC-1980-35c-0188 | | | | Volume
| 35 | |
| 3 | Author
| R. Om, G., EligiuszS. Erafin, JanuszM. Azur | Requires 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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| default:Reihe_C/40/ZNC-1985-40c-0677.pdf | | | | Identifier
| ZNC-1985-40c-0677 | | | | Volume
| 40 | |
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