청국장에서 분리한 바실러스 종으로부터 베타-글루코시다제의 분석 및 부분정제

Identification and Partial Purification of the Extracellular p-Glucosidase of B a c illu s Species Isolated from Cheonggukjang, Fermented Bean Paste

The strain obtained from Cheonggukjang produced a protein showing p-glucosidase activity in the experimental data of column chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. An extracellular p-glucosidase of B acillus species isolated from Cheonggukjang was identified and partially purified through 75% ammonium sulfate precipitation, High Q anion exchange chromatography, and Bio-Gel P-30 and P-60 size exclusion chromatography. The molecular weight of 45,000 dalton was estimated by SDS-PAGE. {3-Glucosidase was produced in the culture medium containing cellobiose, but not produced in glucose medium which may act as a suppressor for the enzyme expression. Assay of |3-glucosidase activity was performed by measuring the release of p-nitrophenol from the substrate p-nitrophenyl-|3-D-glucopyranoside.