豌豆细胞质 NADP 特异性异柠檬酸脱氢酶的纯化与性质研究。
Purification and Characterization of Cytosolic NADP Specific Isocitrate Dehydrogenase from Pisum sativum.
机构信息
Department of Botany/Microbiology, Arizona State University, Tempe, Arizona 85287.
出版信息
Plant Physiol. 1987 Apr;83(4):785-8. doi: 10.1104/pp.83.4.785.
Cytosolic NADP-specific isocitrate dehydrogenase was isolated from leaves of Pisum sativum. The purified enzyme was obtained by ammonium sulfate fractionation, ion exchange, affinity, and gel filtration chromatography. The purification procedure yields greater than 50% of the total enzyme activity originally present in the crude extract. The enzyme has a native molecular weight of 90 kilodaltons and is resolved into two catalytically active bands by isoelectric focusing. Purified NADP-isocitrate dehydrogenase exhibited K(m) values of 23 micromolar for dl-isocitrate and 10 micromolar for NADP, and displayed optimum activity at pH 8.5 with both Mg(2+) and Mn(2+).
从豌豆属植物叶片中分离出胞质 NADP 特异性异柠檬酸脱氢酶。通过硫酸铵分级沉淀、离子交换、亲和和凝胶过滤层析纯化得到该酶。纯化过程中酶的总活性回收率超过粗提物中原始酶活性的 50%。该酶的天然分子量为 90 千道尔顿，等电聚焦将其分为两个具有催化活性的条带。纯化的 NADP-异柠檬酸脱氢酶对 dl-异柠檬酸的 K(m)值为 23 微摩尔，对 NADP 的 K(m)值为 10 微摩尔，在 pH8.5 时，Mg(2+)和 Mn(2+)存在下具有最佳活性。
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