토양으로부터 분리한 호알카리성 세균 Bacillus sp. No. 1911 파쇄하여 유안투석, DEAE-cellulose column chromatography, Sephadex G-150 gel filtration으로 포도당 이성화효소를 정제하여 효소적 특성을 조사하였다. 이 효소는 Sephadex G-200 gel filtration에서 분자량은 170,000으로 측정되었고 SDS-polyacrylamide 전기영동에서 43,000의 단일 band를 얻어, 이 효소는 4개의 동일한 subunit로 구성되었음을 나타내었다. 이 효소는 pH7.5 및 $65^{circ}C$에서 최적활성을 나타내었으며 pH7.5에서 7$0^{circ}C$ 까지 안정하였고 Co$^{++}$ 존재하에 6$0^{circ}C$에서 30분간 가열하였을 때 pH 6-9까지는 비교적 안정되었다.
D-Glucose isomerase (D-xylose ketol isomerase, EC 5.3.1.5) was purified from the Alkalophilic Bacillus sp. No. 1911 by ammonium sulfate precipitation, DEAE-cellulose ion exchange chromatography followed by Sephadex G-150 gel filtration chromatography. Molecular weight of the purified enzyme was estimated to be 11, 000 by gel filtration on Sephadex G-200, and SDS-polyacrylamide gel electrophoresis showed that the enzyme consisted of four identical or similar subunits with a molecular weight of 43, 000. The enzyme was the most active at pH 7.5 and $65^{circ}C$, and stable up to 7$0^{circ}C$ at pH 7.5 and in the range of pH 6-9 at 6$0^{circ}C$ by 30 min incubation in the presence of Co$^{++}$.
