Abstract: The present invention provides a dehydrogenase mutant L283V/L286V, and a preparation method and use thereof, and relates to the field of biomedicine technologies. An amino acid sequence of the mutant L283V/L286V is as shown in SEQ ID NO: 1; and the mutant is prepared by simultaneously mutating 283rd and 286th leucine of a dehydrogenase with an amino acid sequence as shown in SEQ ID NO: 3 into valine. The dehydrogenase mutant L283V/L286V shows high selectivity in catalyzing myosmine reduction reaction in a whole cell system to produce S-nornicotine, and has relatively high dehydrogenase and imine reductase activities, a short enzyme reduction time, and a high transformation rate. The product S-nornicotine obtained through the reaction has extremely high optical purity, which reduces the operation difficulty of subsequent purification.

Abstract: The present invention provides a dehydrogenase mutant L283V/L286V, and a preparation method and use thereof, and relates to the field of biomedicine technologies. An amino acid sequence of the mutant L283V/L286V is as shown in SEQ ID NO: 1; and the mutant is prepared by simultaneously mutating 283rd and 286th leucine of a dehydrogenase with an amino acid sequence as shown in SEQ ID NO: 3 into valine. The dehydrogenase mutant L283V/L286V shows high selectivity in catalyzing myosmine reduction reaction in a whole cell system to produce S-nornicotine, and has relatively high dehydrogenase and imine reductase activities, a short enzyme reduction time, and a high transformation rate. The product S-nornicotine obtained through the reaction has extremely high optical purity, which reduces the operation difficulty of subsequent purification.