Characterization of two ornithine carbamoyltransferases from Pseudomonas syringae pv. phaseolicola,the producer of phaseolotoxin |
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Authors: | O. Jahn J. Sauerstein G. Reuter |
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Affiliation: | (1) WB Mikrobielle Biochemie, Sektion Biologie der Friedrich-Schiller-Universität Jena, Wöllnitzer Str. 7, DDR-6900 Jena, German Democratic Republic;(2) Present address: Forschungszentrum für Bodenfruchtbarkeit der AdL, Müncheberg, Bereich Jena |
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Abstract: | Two ornithine carbamoyltransferases (OCT 1 and OCT 2) were isolated from Pseudomonas syringae pv. phaseolicola and purified by precipitation with ammonium sulfate, heat denaturation, chromatography on DEAE-Sephadex A-50 and Sephadex G-200. Molecular weights of both enzymes: 110,000; optimal activity: pH 8.5 to 9.5 (OCT 1), pH 8.4 (OCT 2); apparent Km for ornithine: 7·10-4 (both enzymes); apparent Km for carbamoylphosphate: 7·10-4 (OCT 1), 2.8·10-3 (OCT 2). Both enzymes possess only an anabolic function. OCT 1 is highly inhibited by low concentrations of phaseolotoxin and Orn-P(O)(NH2)-NH-SO3H, OCT 2 is insensitive to both compounds. The inhibition of OCT 1 is reversible.Non-common abbreviation PNSOrn Ornithine- -P(O)(NH2)-NH-SO3H |
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Keywords: | Pseudomonas syringae pv. phaseolicola Ornithine carbamoyltransferases Phaseolotoxin |
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