The co-immobilization of ketoreductase (KRED) and glucose dehydrogenase (GDH) on highly cross-linked agarose (sepharose) was studied. Immobilization of these two enzymes was performed via affinity interaction between His-tagged enzymes (six histidine residues on the N-terminus of the protein) and agarose matrix charged with nickel (Ni2+ ions). Immobilized enzymes were applied in a semicontinuous flow reactor to convert the model substrate; α-hydroxy ketone. A series of biotransformation reactions with a substrate conversion of >95% were performed. Immobilization reduced the requirement for cofactor (NADP+) and allowed the use of higher substrate concentration in comparison with free enzymes. The immobilized system was also tested on bulky ketones and a significant enhancement in comparison with free enzymes was achieved.
酮还原酶(KRED)和葡萄糖脱氢酶(GDH)在高度交联的琼脂糖(赛法糖)上的共固定化研究。这两种酶的固定化是通过His-标记酶(蛋白质N-末端的六个组氨酸残基)与富含镍(Ni2+离子)的琼脂糖基质之间的亲和作用进行的。固定化酶被应用于半连续流反应器中,用于转化模型底物α-羟基酮。进行了一系列底物转化率>95%的生物转化反应。固定化减少了辅因子(NADP+)的需求,并允许使用更高的底物浓度,与游离酶相比。固定化系统还在庞大的酮类化合物上进行了测试,并取得了与游离酶相比显著的增强效果。