Patent ID: 11198896

Abstract:
One aspect of the invention provides a nucleic acid encoding a 7β-hydroxysteroid dehydrogenase (7β-HSDH) that catalyzes at least the stereospecific enzymatic reduction of a 7-ketosteroid to the corresponding 7-hydroxysteroid. The enzyme includes a mutation at position 64 of SEQ ID NO:2 or in the corresponding sequence positions of an amino acid sequence derived therefrom with at least 90% sequence identity to SEQ ID NO:2. The mutation at position 64 is the mutation R64X1, wherein X1 represents E, D, T, L, S, P, V, K, C, A, G, Q, F, W, I or Y. The enzyme shows the following property profile in comparison with the 7β-HSDH with SEQ ID NO:2: (a) an increased specific activity (Vmax [U/mg]) for NADPH in the enzymatic reduction of dehydrocholic acid (DHCA) with NADPH as cofactor.