A potential anti-oxidant protein in a ferrous iron-oxidizing Sulfolobus species |
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Authors: | Nicolas P Burton Timothy D Williams Paul R Norris |
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Institution: | Division of Microbial and Molecular Ecology, The Alexander Silverman Institute of Life Sciences, and the Moshe Shilo Center for Marine Biogeochemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel |
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Abstract: | Abstract Eight species of halophilic Archaea were tested for the presence of isocitrate lyase activity. High activities (up to 100 nmol min?1 mg protein?1) were detected in Haloferax mediterranei and Haloferax volcanii when grown in medium containing acetate as the principal carbon source. Little activity was found in representatives of the genera Halobacterium and Haloarcula . Isocitrate lyase from Haloferax mediterranei required high potassium chloride concentrations, optimal activity being found at 1.5–3 M potassium chloride and pH 7.0. Replacement of potassium chloride by sodium chloride resulted in much lower activities. Sulfhydryl compounds (cysteine, glutathione) were not stimulatory. In other properties (stimulation by magnesium ions, sensitivity to different inhibitors) the enzyme resembled isocitrate lyases from representatives of the Bacteria and Eucarya. |
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Keywords: | Isocitrate lyase Halophilic Archaea Acetate metabolism |
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