Abstract
The membrane fraction of Gluconobacter oxydans IFO 3244, involving membrane-bound quinoprotein quinate dehydrogenase and 3-dehydroquinate dehydratase, was immobilized into Ca-alginate beads. The Ca-alginate-immobilized bacterial membrane catalyzed a sequential reaction of quinate oxidation to 3-dehydroquinate and its spontaneous conversion to 3-dehydroshikimate under neutral pH. An almost 100% conversion rate from quinate to 3-dehydroshikimate was observed. NADP-Dependent cytoplasmic enzymes from the same organism, shikimate dehydrogenase and D-glucose dehydrogenase, were immobilized together with different carriers as an asymmetric reduction system forming shikimate from 3-dehydroshikimate. Blue Dextran 2000, Blue Dextran-Sepharose-4B, DEAE-Sephadex A-50, DEAE-cellulose, and hydroxyapatite were effective carriers of the two cytoplasmic enzymes, and the 3-dehydroshikimate initially added was converted to shikimate at 100% yield. The two cytoplasmic enzymes showed strong affinity to Blue Dextran 2000 and formed a soluble form of immobilized catalyst having the same catalytic efficiency as that of the free enzymes. This paper may be the first one on successful immobilization of NAD(P)-dependent dehydrogenases.
