| Popis: |
Living microbial cells were immobilized into polyacrylamide gel (PAAG) and used to perform the following processes of steroid transformation: 1,2-dehydrogenation, 20 β-reduction, 17 β-reduction, 11α- and 11 β-hydroxylation, transformation of sterines, and hydrolysis of steroid ethers (1, 2). Cells of Arthrobacter globiformis with 3-ketosteroid-Δ1-dehydrogenase activity and Sacch. cerevisiae with 17 β-hydroxysteroid dehydrogenase activity were immobilized by various techniques: entrapment into PAAG, polyvinyl alcohol membranes, and photo-crosslinkable resins, adsorption on carriers, and covalent binding with activated silica gel. In all cases 3-ketosteroid-Δ1-dehydrogenase activity was practically equal to the activity of the free cells and made up 0.14 µmole/mg cells/min; with 17 β-hydroxysteroid dehydrogenase the activity of the immobilized yeasts was far less than the activity of the free cells. |
