【摘要】 经改造的植酸酶功能区结构基因按正确的阅读框架融合到酿酒酵母 (S .cerevisiae)表达载体YFD59上的α-因子信号肽编码序列 3’端 ,并受PGK组成型启动子和ADH1终止子的控制。重组载体以乙酸锂方法转化酿酒酵母宿主菌株BJ1 991 ,经尿嘧啶筛选得到酵母转化子。限制性培养酵母转化子并测定表达产物的生物活性。研究证明 ,植酸酶基因功能区具有生物学活性。表达产物与完整植酸酶相比 ,其 pH适性相似 ,但耐温性降低更多还原

【Abstract】 The gene coding for extracellular, glycosylated phytase(phytA) from Aspergillus ficuum NRRL3135 was cloned partially (active domain), without its intron and SP coding region. After being inserted into a S cerevisiae high-efficiency expression vector YFD59, under control of PGK constitutive promotor and ADH1 terminator, the manipulated phytA gene fragment merged with the 3’end of a - factor coding sequence correctly for translation, which had been comfirmed by DNA sequencing. Then the S.cerevisiae host BJ1991 was transformed with the recombinant expression vector by the method of Lithium Acetate. Yeast transformants were selected by URA3 selection, then cultured in YNB medium. Phytase activity was detected, revealing the expression product could be secreted efficiently with normal biological founction ( nearly 12 fold of that of the wt BJ1991). Compared with wild-type PhytA, the expression product posses similar pH adaptability, however lower temperature resistance.更多还原