嗜热地衣芽孢杆菌植酸酶的原核表达及酶学性质研究

Expression and characteristics of phytase from Bacillus licheniformis

摘要: 将地衣芽孢杆菌SR01（Bacillus licheniformis SR01）的植酸酶phy基因重组于表达载体p GEX-4T-3中,导入大肠杆菌BL21（Escherichia coli BL21）构建工程菌p GX1143,并得到了高效表达。对其酶学性质的研究表明:该酶最适反应p H为5.0,最适反应温度为55℃,具有广泛的p H稳定性和较好的热稳定性;Co²⁺)、Li⁺、Mg²⁺)和Ba²⁺对酶活性有促进作用,Cu²⁺、Pb²⁺、Fe²⁺、Ag⁺、SDS对酶活性有不同程度的抑制作用,并且Pb²⁺、Fe²⁺和SDS对酶活性的抑制作用较强烈;此外,该酶还具有非常好的抗胰蛋白酶水解能力和部分抗胃蛋白酶水解的能力。

Abstract: The gene phy,from a thermophilic bacteria strain Bacillus licheniformis SR01,was cloned into prokaryotic expression vector p GEX-4T-3 to construct the recombinant strain p GX1143,and it was successfully efficiently expressed. The optimal p H and temperature for this phytase activity were 5.0 and 55 ℃,respectively. The enzyme had a wide range of p H stability and good thermal stability. And it was activated by Co²⁺,Li⁺,Mg²⁺,Ba²⁺,and inhibited by Cu²⁺,Pb²⁺,Fe²⁺,Ag⁺,SDS. However,it almost lost activity when influenced by Pb²⁺,Fe²⁺ and SDS. In addition,it had strong ability to resist hydrolyzation by trypsin and partial ability to resist hydrolyzation by pepsin.