Coupled, self-sufficient biotransformation of chenodeoxcholic acid to ursodeoxycholic acid and novel enzyme mutants applicable in said process
AssigneePharmaZell GmbH
InventorsDaniel Bakonyi, Werner Hummel, Ralf Gross
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Abstract
The present invention relates to a coupled biotransformation process of converting chenodeoxycholic acid (CDCA) and related compounds to ursodeoxycholic acid (UDCA) and related compounds. It also relates to the cloning, expression, and biochemical characterization of a novel NADP+-dependent 7α-hydroxysteroid dehydrogenase (7α-HSDH) from Clostridium difficile, cofactor switch mutants thereof, and their application for the oxidation of bile acids. A further aspect of the invention relates to novel NADP-dependent cofactor switch mutants of the NADP+-dependent 7α-HSDH of E. coli and their application for the oxidation of bile acids.
Claims15
A mutant of Clostridium difficile 7α-hydroxysteroid dehydrogenase (7α-HSDH) of SEQ ID NO:
- 34, wherein the mutant catalyzes at least the stereospecific enzymatic oxidation of 7α-hydroxysteroids to the corresponding 7-ketosteroids under consumption of NAD+ as cofactor, wherein the mutant comprises a mutation of at least one amino acid position of SEQ ID NO:
- 34 selected from the group consisting of K16, A37 and R38, wherein said mutation is selected from the group consisting of single mutation K16X1, single mutation A37X2, single mutation R38X3, double mutation K16X1/A37X2 and double mutation A37X2/R38X3, wherein
- X1 represents A, G, or D
- X2 represents D or E and
- X3 represents I,
- and wherein the amino acid sequence of the mutant has an amino acid sequence identity of at least 90% to the amino acid sequence of SEQ ID NO:
- 34.
Dependencies are inferred from the claim text.