Purification and Characterization of Cyclodextrin Glycosyltransferase from Alkalophilic Bacillus sp

호알카리성 Bacillus sp.의 cyclodextrin glycosyltransferase의 정제와 특성

Alkalophilic sp. YC-335 isolated from soil was capable of producing large amount of cyclodextrin glycosyltransferase (CGTase) in culture broth. This enzyme was successively purified 52.9 folds with 17.8 yield by ethanol precipitation, DEAE-Toyopearl column chromatography and Sephadex G-100 column chromatography. The purified enzyme have a molecular weight of approximately 75,000 estimated by SDS polyaerylamide gel electrophoresis. The optimum pH and temperature for the enzyme activity were 6.0 and 5$0^{\circ}C$, respectively. The enzyme stable between pH 6 and 10, and up to 5$0^{\circ}C$. The thermostability of the enzyme was increased up to 6$0^{\circ}C$ by the addition of 15mM CaCl$_2$.

토양에서 분리한 호알카리성 Bacillus sp. YC-335가 생산하는 CGTase를 ethanol 침전법, DEAE-Toyopearl column chromatography, Sephadex G-100 column chromatography 방법 등에 의해 대량 정제 하였다. 이때 수율은 17.8 이었고 52.9배의 정제도를 가진 효소단백질을 얻을 수 있었다. 정제효소는 SDS-polyacrylamide gel 전지영동에 의해 분자량이 75,000 정도인 단일 peptide의 단백질임을 확인하였고 효소의 최적활성 pH는 6.0 있었으며 pH 안정성은 pH 6-10까지 안정하였다. 최적활성온도는 5$0^{\circ}C$이었으며 열안정성은 5$0^{\circ}C$까지 안정하였고 이는 15mM CaCl$_2$에 의해 열안정성이 보호되었다.