논문 상세보기
pp.87-94
제주산 키위에서 추출 정제한 단백분해효소의 특성을 조사하였다. 본 효소는 DEAE-Toyopearl 650C, Sephadex G-100 chromatography에 의해 정제하였고 비활성은 8.5배 증가하고 회수율은 25%이었다. 이 효소는 40℃, pH 7에서 최대활성을 나타내었으며 30∼50℃, pH 5.0∼9.0사이에서 안정하고 K_m값은 32 mM, 분자량은 27, 000으로 추정된다. Hg^+, Co^2- 이온에 의해 활성이 저해되며 phenylmercuric acetate, leupeptin에 의해 저해되므로 활성부위에 thiol기를 갖는 것으로 추정되어진다.
A protease, actinidin, was isolated from Cheju kiwi fruit Actinidia chinesis. The enzyme was purified about 8.5 fold with the yield of 25% by column chromatographies of DEAE-Toyopearl and Sephadex G-100. Purified enzyme gave a single protein band on polyacrylamide gel electrophoresis and its molecular weight estimated by SDS-PAGE was about 27, 000. The optimum pH and temperature were 7.0 and 40℃, respectively. This enzyme was stable at the ranges of pH 5.0∼9.0 and below 50℃. It was also found that Fe^+2, Fe^+3, and Na^+ ions increased the enzyme activity, whereas Hg^+2 and Co^+2 ions decreased. The enzyme was inhibited by phenylmercuric acetate and leupeptin, which indicated that active center of the enzyme had thiol-group. The enzyme reaction followed the Michaelis-Menten kinetics with the K_m value of 0.32 mM for casein.
