丁香假单胞菌菜豆致病变种（菜豆毒素产生菌）中两种鸟氨酸氨甲酰基转移酶的特性分析
Characterization of two ornithine carbamoyltransferases from Pseudomonas syringae pv. phaseolicola, the producer of phaseolotoxin.
作者信息
Jahn O, Sauerstein J, Reuter G
出版信息
Arch Microbiol. 1987 Mar;147(2):174-8. doi: 10.1007/BF00415280.
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 X 10(-4) (both enzymes); apparent Km for carbamoyl-phosphate: 7 X 10(-4) (OCT 1), 2.8 X 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.
从菜豆假单胞菌中分离出两种鸟氨酸氨甲酰基转移酶（OCT 1和OCT 2），并通过硫酸铵沉淀、热变性、DEAE-葡聚糖A-50和葡聚糖G-200柱层析进行纯化。两种酶的分子量均为110,000；最佳活性：pH 8.5至9.5（OCT 1），pH 8.4（OCT 2）；鸟氨酸的表观Km值：7×10⁻⁴（两种酶）；氨甲酰磷酸的表观Km值：7×10⁻⁴（OCT 1），2.8×10⁻³（OCT 2）。两种酶仅具有合成代谢功能。OCT 1受到低浓度菜豆毒素和Orn-P(O)(NH2)-NH-SO3H的强烈抑制，OCT 2对这两种化合物均不敏感。OCT 1的抑制作用是可逆的。
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