Asymmetric Reductive Amination of Structurally Diverse Ketones with an Engineered Amine Dehydrogenase.

Herein, an engineered amine dehydrogenase is developed as an exemplary closed-boundary catalytic system for addressing the substrate scope-enantioselectivity dilemma. Asymmetric reductive amination with essentially quantitative enantioselectivity is demonstrated, with a K68S, N261L, A113G, T134G mutant of Bacillus species REN16 Glu/Leu/Phe/Val amino acid dehydrogenase for structurally diverse ketones. Reciprocal conformational adaptation, with complementary matching of conformational flexibility and sterics on both the enzyme and substrate sides, is proposed as the working mechanism.