来源于Kosakonia radicincitans的新型植酸酶基因通过密码子优化在毕赤酵母中高效表达

Codon optimization of a novel phytase gene from Kosakonia radicincitans for high-level expression in Pichia pastoris

将来源于Kosakonia radicincitans的新型植酸酶基因(以下命名为KrPhyS)进行密码子优化,并将其导入到毕赤酵母GS115中进行表达。结果表明:KrPhyS的蛋白分泌量可积累到45μg/mL;该酶的比活力为1.83×10~3 U/mg,最适pH为3.5,最适温度为55℃,在65℃下热稳定性较高,在pH 3.5—7.5时该酶比较稳定。以植酸钠作为底物,EDTA和Mg^(2+)等金属离子对该酶有一定的激活作用;Cu^(2+)等金属离子对该酶有一定的抑制作用。该酶还具有良好的抗胃蛋白酶水解的能力。

A novel phytase gene KrPhyS from Kosakonia radicincitans was synthesized with codon optimization and introduced into Pichia pastoris GS115 for expression. The results showed that the secretion yield of recombinant phytase （KrPhyS） could be accumulated to 45 μg/mL. The specific activity of the enzyme was 1.83×10^3 U/rag, the optimum pH was 3.5, the optimum temperature was 55℃ ; the thermal stability was higher at 65℃, the enzyme was stable at pH 3.5--7.5. With sodium phytate as substrate, EDTA, Mg2＋ and other metal ions had a certain activation effect on the enzyme activity, Cu2＋ and other metal ions had a inhibitory effect on the enzyme activity. The enzyme also had good resistance to pepsin hydrolysis.