固定化E.Coli JM109(pBR322-MAT)细胞催化合成S-腺苷蛋氨酸

Biosynthesis of S-adenosylmethionine by immobilized whole cell of E.Coli JM109(pBR322-MAT)

通过PCR从大肠杆菌(E.Coli-K12)基因组DNA中扩增出甲硫氨酸腺苷转移酶(MAT)基因,构建了能高效表达MAT的重组大肠杆菌E.ColiJM109(pBR322-MAT)。选择海藻酸钙(CA)凝胶包埋固定化重组大肠杆菌,研究发现最佳ρ(CA)为20g/L的水溶液,最适细胞包埋量为0.15 g(湿细胞)/mL(凝胶),连续反应5批次后固定化细胞酶活力为初始最高酶活力的91%。对于固定化细胞催化合成SAM,在最佳条件下底物ATP的转化率超过95%。

The methionine adenosyhransferase （MAT） gene is cloned from the genome of E. Coli-K12, and the recombinant E. Coli JM109（pBR322-MAT） strain which can highly express MAT is constructed. The whole cells of E. Coli JM109 （pBR322-MAT） are immobilized in Ca-alginate（CA） gel. The optimal mass concentration of CA is 20 g/L and the optimal cell loading by direct entrapment is 0.15 g of wet weight cells per mL gel. After 5 batches of reaction, the enzyme activity decreases to 91% of the initial. For the biosynthesis of S- adenosylmethionine by immobilized cell, the conversion rate based on the amount of ATP can be over 95% under the optimal conditions.