Novel ketose 3-epimerase and application thereof in production of D-psicose

The invention discloses novel ketose 3-epimerase and application thereof in production of D-psicose, and belongs to the technical field of gene engineering and enzyme engineering, the gene nucleotide sequence of the novel ketose 3-epimerase is as shown in SEQ ID NO.1, and the amino acid sequence of the novel ketose 3-epimerase is as shown in SEQ ID NO.2. Experiments prove that the conversion rate of the MDAE enzyme for catalyzing conversion of D-fructose into D-psicose is 34.1%, and the MDAE enzyme is the enzyme with the highest conversion rate so far. The enzyme shows more than 90% of relative activity in a pH range of 7.0-8.6, and 86% of activity can be retained after incubation at 75 DEG C for 4 hours. Results show that the MDAE enzyme has high enzyme activity under neutral, acidic and alkaline conditions and at a high temperature, has high conversion rate and good stability, is suitable for being applied to high-yield D-psicose, and lays an important foundation for industrial production of D-psicose. 本发明公