(254f) Activity Improvement of D-Psicose-3-Epimerase from Agrobacterium tumefaciens CGMCC 1.1488 By Site-Directed Mutagenesis

The enzyme D-psicose-3-epimerase catalyzes the conversion of C3-epimerization from fructose to allulose (D-psicose). Due to the relatively low allulose conversion rate, the improvement of enzymatic activity by site-directed evolution was carried out in this experiment. The DPEase-C58 from Agrobacterium tumefaciens CGMCC 1.1488 was supplied to the protein structure comparison and sequence alignment with DTE from Pseudomonas cichorii, whose crystal structure and the complex with D-fructose had been determined, to conduct the sites mutagenesis. The two sites of saturation mutation of H228 and T231 were carried out. At first round 5 mutants with 20% relevant higher than wide-type were obtained by high-throughout screening method.