Itoh N, Izumi Y, Yamada H
J Biol Chem. 1986 Apr 15;261(11):5194-200.
Bromoperoxidase was purified from the crude extract of Corallina pilulifera to be homogeneous upon polyacrylamide disc gel and sodium dodecyl sulfate-polyacrylamide gel electrophoreses according to the procedures previously reported (Itoh, N., Izumi, Y., and Yamada, H. (1985) Biochem. Biophys. Res. Commun. 131, 428-435). The enzyme had a molecular weight of approximately 790,000 and was composed of 12 subunits of identical molecular weights (Mr 64,000). Hexagonal molecular shapes of the enzyme were observed by electron microscopy. The isoelectric point of the enzyme was 3.0, and the predominance of acidic amino acids was revealed by amino acid analysis of the enzyme. The enzyme was specific for I- and Br- and inactive toward Cl- and F-. The optimum pH of the enzyme was 6.0, and the enzyme was stable in a range from pH 5.0 to 11.0. The enzyme had no hemeor flavin-like compounds as a prosthetic group. Plasma emission spectroscopy revealed that the enzyme contains 2.3 +/- 0.2 atoms of iron and 1.6 +/- 0.1 atoms of magnesium/molecule of protein. Hence, bromoperoxidase of C. pilulifera was distinct from other haloperoxidases and many peroxidases, which are hemoproteins.
根据之前报道的方法（Itoh, N., Izumi, Y., and Yamada, H. (1985) Biochem. Biophys. Res. Commun. 131, 428 - 435），从海萝的粗提物中纯化出溴过氧化物酶，经聚丙烯酰胺圆盘凝胶电泳和十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳后呈均一状态。该酶的分子量约为790,000，由12个分子量相同（Mr 64,000）的亚基组成。通过电子显微镜观察到该酶呈六边形分子形状。该酶的等电点为3.0，氨基酸分析表明其酸性氨基酸占优势。该酶对I⁻和Br⁻具有特异性，对Cl⁻和F⁻无活性。该酶的最适pH为6.0，在pH 5.0至11.0的范围内稳定。该酶不含作为辅基的血红素或类黄素化合物。等离子体发射光谱显示，该酶每分子蛋白质含有2.3±0.2个铁原子和1.6±0.1个镁原子。因此，海萝的溴过氧化物酶与其他卤过氧化物酶和许多作为血红蛋白的过氧化物酶不同。
