키위열매 Protease 의 추출 정제 및 그 특성에 대하여

Purification and Characterization of Kiwifruit Protease

Kiwifruit에서 pretense를 추출 정제하여 그의 특성을 검토하였다. 조효소는 유안분획, sephadex G-100 filtration 및 DEAE-sephadex A-50 column chromatography를 거쳐 정제되었으며 정제효소의 비활성은 30.10으로 10.95배 증가하였고 활성수율은 7.48%에 달하였다. 정제효소는 casein및 hemoglobin을 잘 분해하였고 작용 최적 pH는 7.0이었으며 pH$7.0{\sim}8.0$에서 안정하였고 작용 최적온도는 $45^{\circ}C$이고 $50^{\circ}C$이하에서 안정하였다. 0.5 mM $HgCl_2$와 $MnSO_4$에 의해 강한 저해를 받았으며 2 mM cysteine과 0.5 mM EDTA에 의해 활성이 촉진되었으며 Km값은 50.5 mg/ml 이었고 분자량은 SDS 전기영동법에 의하여 측정하였을 때 23,500이었다.

These studies were conducted to investigate the purification and characterization of Kiwifruit protease, and the results obtained were as follows The protease was purified by ammonium sulfate fractionation, Sephadex G-100 filtration and DEAE-Sephadex A-50 column chromatography and purified enzyme gave a single protein band on polyacrylamide gel electrophoresis The specific activity of purified enzyme was 30,10 units/mg protein and the yield was 7.48. The purified enzyme showed a high affinity for casein and hemoglobin. The optimal pH and temperature for enzyme activity were 7.0 and $45^{\circ}C$, respectively. The enzyme activity was strongly inhibited by $HgCl_2,\;MnSO_4$. However. the enzyme was activated by cysteine and EDTA. The Michaelis constant for casein was calculated to be 50.5mg/ml according to the Line weaver-Burk method, and its molecular weight was determied as 23,500 by polyacrylamide gel electrophoresis.