abstract |
The present invention relates to novel 7β-hydroxysteroid dehydrogenase mutants, sequences encoding these mutants, methods for preparing mutants and their enzymatic reactions in bile acid compounds, especially in the preparation of ursodeoxycholic acid ( UDCS); The present invention also relates to a novel method for synthesizing UDCS using enzyme mutants; and using recombined, multiple modified microorganisms to prepare UDCS. |