芽孢杆菌中一种铬酸盐还原酶的纯化及部分特性鉴定
Purification and partial characterization of a chromate reductase from Bacillus.
作者信息
Campos-García J, Martínez-Cadena G, Alvarez-González R, Cervantes C
机构信息
Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana, Morelia.
出版信息
Rev Latinoam Microbiol. 1997 Jan-Jun;39(1-2):73-81.
A soluble NADH-dependent enzyme capable of reducing hexavalent chromium [Cr(VI)] to the trivalent form [Cr(III)] was purified from chromate-resistant Bacillus QC1-2. An enriched single protein band of 24 kDa was observed by SDS-PAGE following HPLC ion-exchange and size-exclusion procedures. In the latter step, the chromate reductase showed a molecular mass of 44 kDa, which suggested that the enzyme consists of two subunits of about 24 kDa. Purified chromate reductase displayed optimal activity at a temperature and pH of 37 degrees C and 7.0, respectively. The enzyme showed a Km of 0.35 mM for chromate and a Vmax of 50 nmol Cr(VI) reduced per minute per mg protein.
从耐铬芽孢杆菌QC1-2中纯化出一种可溶的依赖烟酰胺腺嘌呤二核苷酸（NADH）的酶，该酶能够将六价铬[Cr(VI)]还原为三价形式[Cr(III)]。经过高效液相色谱（HPLC）离子交换和尺寸排阻程序后，通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）观察到一条富集的24 kDa单蛋白条带。在最后一步中，铬酸盐还原酶的分子量为44 kDa，这表明该酶由两个约24 kDa的亚基组成。纯化后的铬酸盐还原酶在温度37℃和pH 7.0时表现出最佳活性。该酶对铬酸盐的米氏常数（Km）为0.35 mM，最大反应速率（Vmax）为每毫克蛋白质每分钟还原50 nmol Cr(VI)。
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