Streptomyces GI 32 방선균의 Glucose Isomerase 생산과 효소특성

Studies on the Production and Characteristics of Glucose Isomerase from Steptomyces sp. GI 32.

토양에서 분리, 동정한 Steptomyces sp. GI 32의 glucose isomerase 생산은 sorbitol 1%, yeast extract 0.4%, tryptore 0.6%, 1 mM Fe$_2$(SO$_4$)$_3$의 조성을 가진 배지에서 초기 pH 7.0으로 조절하여 35$^{\circ}C$에서 약 18시간 진탕배양시 효소생산량이 최고로 240 units/mg이었다. 효소는 ammonium sulfate 분획, DEAE cellulose chromatography 등의 과정을 거쳐 부분정제한 결과 3배정도 효소 비활성이 증가하였다. 효소활성의 치적온도는 7$0^{\circ}C$이며, 최적 pH는 8.0이었다. 특히 효소의 열안정성이 7$0^{\circ}C$에서 1시간 가열하여도 전혀 실활되지 않았다.

Steptomyces sp. GI 32 with high production of glucose isomerase was isolated from soil. The maximum enzyme production was observed in the culture medium containing 1% sorbitol, 0.6% tryptone, 0.4% yeast extract, 1mM Fe$_2$(SO$_4$)$_3$ with initial pH 7.0 when the cell was cultured at 35$^{\circ}C$ about 18 hours with shaking. The enzyme was partially purified by ammonium sulfate fractionation and DEAE cellulose chromatography. The enzyme was also appeared to be relatively thermostable, and no apopreciable inactivation was observed after incubation at 7$0^{\circ}C$ for 1 hour. The optimal pH and temperature of the enzyme were pH 8.0 and 7$0^{\circ}C$, respectively.