Zeida M, Wieser M, Yoshida T, Sugio T, Nagasawa T
Department of Biological Function & Genetic Resources Sciences, Faculty of Agriculture, Okayama University, Tsushima Naka, Okayama 700-11, Japan.
Appl Environ Microbiol. 1998 Dec;64(12):4743-7. doi: 10.1128/AEM.64.12.4743-4747.1998.
Oxygen-sensitive gallic acid decarboxylase from Pantoea (formerly Enterobacter) agglomerans T71 was purified from a cell extract after stabilization by reducing agents. This enzyme has a molecular mass of approximately 320 kDa and consists of six identical subunits. It is highly specific for gallic acid. Gallic acid decarboxylase is unique among similar decarboxylases in that it requires iron as a cofactor, as shown by plasma emission spectroscopy (which revealed an iron content of 0.8 mol per mol of enzyme subunit), spectrophotometric analysis (absorption shoulders at 398 and 472 nm), and inhibition of the enzyme activity by 2,2'-bipyridyl, o-phenanthroline, and EDTA. Another interesting feature of this strain is the fact that it contains a tannase, which is used together with the gallic acid decarboxylase in a two-enzyme resting cell bioconversion to synthesize valuable pyrogallol from readily available tannic acid.
从成团泛菌(以前称为聚团肠杆菌)T71中提取的对氧敏感的没食子酸脱羧酶,在经过还原剂稳定处理后从细胞提取物中纯化得到。这种酶的分子量约为320 kDa,由六个相同的亚基组成。它对没食子酸具有高度特异性。没食子酸脱羧酶在类似的脱羧酶中是独特的,因为它需要铁作为辅因子,这通过等离子体发射光谱法(显示每摩尔酶亚基的铁含量为0.8摩尔)、分光光度分析(在398和472 nm处有吸收峰)以及2,2'-联吡啶、邻菲罗啉和EDTA对酶活性的抑制作用得以证明。该菌株的另一个有趣特征是它含有一种单宁酶,在双酶静息细胞生物转化中,单宁酶与没食子酸脱羧酶一起用于从容易获得的单宁酸合成有价值的焦性没食子酸。