Greiner Ralf, Farouk Abd-ElAziem
Centre for Molecular Biology, Federal Research Centre for Nutrition and Food, Haid-und-Neu-Strasse 9, D-76131, Karlsruhe, Germany.
Protein J. 2007 Oct;26(7):467-74. doi: 10.1007/s10930-007-9086-z.
A periplasmatic phytase from a bacterium isolated from Malaysian waste water was purified about 173-fold to apparent homogeneity with a recovery of 10% referred to the phytase activity in the crude extract. It behaved as a monomeric protein with a molecular mass of about 42 kDa. The purified enzyme exhibited a single pH optimum at 4.5. Optimum temperature for the degradation of phytate was 65 degrees C. The kinetic parameters for the hydrolysis of sodium phytate were determined to be KM=0.15 mmol/l and kcat=1164 s(-1) at pH 4.5 and 37 degrees C. The purified enzyme was shown to be highly specific. Among the phosphorylated compounds tested, phytate was the only one which was significantly hydrolysed. Some properties such as considerable activity below pH 3.0, thermal stability and resistance to pepsin make the enzyme attractive for an application as a feed supplement.
从马来西亚废水中分离出的一种细菌的周质植酸酶被纯化了约173倍，达到表观均一性，相对于粗提物中的植酸酶活性，回收率为10%。它表现为一种分子量约为42 kDa的单体蛋白。纯化后的酶在pH 4.5时表现出单一的最适pH值。植酸盐降解的最适温度为65℃。在pH 4.5和37℃下，植酸钠水解的动力学参数测定为KM = 0.15 mmol/l，kcat = 1164 s(-1)。纯化后的酶具有高度特异性。在所测试的磷酸化化合物中，植酸盐是唯一被显著水解的物质。该酶在pH 3.0以下具有相当的活性、热稳定性和对胃蛋白酶的抗性等一些特性，使其作为饲料添加剂具有应用吸引力。
