Cyclodextrinase from B. stearothermophilus KJ16 that can produce both cyclodextrin(CD) glucanotransferase and cyclodextrinase was purified 87.6-fold with 7% yield by ammonium sulfate precipitation, DEAE-cellulose chromatography, Sephadex G-100 chromat...
Cyclodextrinase from B. stearothermophilus KJ16 that can produce both cyclodextrin(CD) glucanotransferase and cyclodextrinase was purified 87.6-fold with 7% yield by ammonium sulfate precipitation, DEAE-cellulose chromatography, Sephadex G-100 chromatography, and FPLC. The molecular weight of the purified enzyme was about 68,000 dalton by SDS-PAGE. The optimal pH and temperature were 6.0 and 55℃, respectively. The enzyme was stable at 50℃ for 2 hr and in the pH range of 5.5 and 8.5. The enzyme activity was inhibited strongly by mercaptoethanol, dithiothreitol, p-chloromercuribenzoate, N-bromosuccinimide, Cu^+2 and Hg^+2. The purified enzyme hydrolyzed CDs with γ-CD$gt;β-CD$gt;α-CD. The enzyme also hydroylzed linear maltodextrins and polysaccharieds, but the rates of hydrolysis for such substrates were slow as compared to that for γ-CD. The final degradation products with all substrates were maltose and glucose. Maltose was not further hydrolyzed.