Polyethylene glycol과 Potassium phosphate buffer가 이루는 액체 2 상계를 이용하여 Bacillus subtilis에서 생산된 neutral protease를 counter-current distribution으로 정제하였고 ammonium sulfate, DEAE-cellulose, CM-cellulose 이온교환 chromatography를 이용한 일반적인 정제법과 비교해 보았다. 그 결과 counter-current distribution을 이용하여 조효소액보다 30배 높은 specific activity를 얻었는데 이 값은 일반적인 정제법으로 얻은 10.9배보다 약 3배 높은 값이었다. 따라서 counter-current distribution에 의한 정제가 재래식 정제법보다 단순하며 더 높은 정제효과를 얻을 수 있음을 확인할 수 있었다.
Using Polyethylene glycol/Potassium phosphate buffer aqueous two-phase systems, the neutral protease from Bacillus subtilis was purified by the counter-current distribution, and the result were compared with the conventional methods including ammonium sulfate fractionation, DEAE-cellulose and CM-cellulose ion exchange chromatography. In the counter-current distribution transferring 31 tubes of PEG/PPB systems, the maximum protease activity was appeared at the 7th tube and the purification fold was 30.1 fold of the crude enzyme. This value was about 3 times larger than the purification fold of the conventional method.
