Purification and Some Properties of Cyclodextrin Glucanotransf erase from Bacillus stearothermophilus TC-60

Abstract

Cyclodextrin glucanotransferase [EC. 2. 4. 1. 19] from Bacillus stearothermophilus TC-60 was purified by starch adsorption, DEAE-Sephadex column chromatography and Biogel P-150 gel filtration. Subunit molecular weight of the purified enzyme was estimated to be 68, 000 by sodium dodecylsulfate-polyacrylamide gel electrophoresis. The isoelectric point of the purified enzyme was pH 4.5. The enzyme was most active at pH 6.0 and at 70°C, and stable up to 50°C at pH 7.0 and in the range of pH 7.0-9.2 at 40°C in the 2-hr incubation . The results of the trichloroethylene-test and the Tilden-Hudson test suggest that the enzyme from B, stearothermophilus produced cyclodextrins in a different ratio from the enzymes of B, megaterium. and B. macerans IFO 3490.