OCCURRENCE OF ENZYMES INVOLVED IN BIOSYNTHESIS OF INDOLE-3-ACETIC-ACID FROM INDOLE-3-ACETONITRILE IN PLANT-ASSOCIATED BACTERIA, AGROBACTERIUM AND RHIZOBIUM
OCCURRENCE OF ENZYMES INVOLVED IN BIOSYNTHESIS OF INDOLE-3-ACETIC-ACID FROM INDOLE-3-ACETONITRILE IN PLANT-ASSOCIATED BACTERIA, AGROBACTERIUM AND RHIZOBIUM
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DOI：
10.1073/pnas.92.3.714
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发表时间：
1995-01-31
影响因子：
11.1
通讯作者：
SHIMIZU, S
中科院分区：
文献类型：
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作者：
KOBAYASHI, M;SUZUKI, T;SHIMIZU, S
在植物病原菌根癌农杆菌和豆科植物根瘤菌中发现了一条迄今未知的途径，该途径涉及两种酶的作用，一种是腈水合酶，一种是酰胺酶，用于生物合成吲哚-3-乙酸。作用于吲哚-3-乙腈的腈水合酶只需两步就可从根癌农杆菌的无细胞提取物中纯化到均一。经高效液相色谱仪测定，该酶的相对分子质量约为102 kDa，由四个分子量相同的亚基组成。该酶在可见光范围内有较宽的吸收光谱，最大吸收波长分别为408 nm和705 nm，且含有钴和铁。该酶按化学计量比催化吲哚-3-乙腈水合成吲哚-3-乙酰胺，比活力为13.7mU/min/mg，K-m为7.9mU/m。
The occurrence of a hitherto unknown pathway involving the action of two enzymes, a nitrile hydratase and an amidase for the biosynthesis of indole-3-acetic acid was discovered in phytopathogenic bacteria Agrobacterium tumefaciens and in leguminous bacteria Rhizobium. The nitrile hydratase acting on indole-3-acetonitrile was purified to homogeneity through only two Steps from the cell-free extract of A. tumefaciens. The molecular mass of the purified enzyme estimated by HPLC was about 102 kDa, and the enzyme consisted of four subunits identical in molecular mass. The enzyme exhibited a broad absorption spectrum in the visible range with absorption maxima at 408 nm and 705 nm, and it contained cobalt and iron. The enzyme stoichiometrically catalyzed the hydration of indole-3-acetonitrile into indole-3-acetamide with a specific activity of 13.7 mu mol per min per mg and a K-m of 7.9 mu M.