The Kinetics of the Reaction of Thiocyanate and Nitrite Ions with Orconectes limosus Oxyhemocyanin
Open Access
- 1 August 1985
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung C
- Vol. 40 (9-10) , 677-681
- https://doi.org/10.1515/znc-1985-9-1016
Abstract
The time course of the reaction of oxyhemocyanin from the arthropod Orconectes limosus with SCN− and NO2 − was investigated. After addition of one of these anions to oxyhemocyanin solution an exponential decay of A340 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 NO2 − 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.Keywords
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