Penicillium sp. LAM 91-89가 생산하는 bilirubin oxidase의 특성

Properties of a bilirubin oxidase from Penicillium sp. LAM 91-89

토양에서 분리한 bilirubin oxidase를 생산하는 Penicillium sp. LAM 91-89의 배양액으로부터 효소를 정제하여 여러가지 성질을 조사하였다. LAM 91-89 billirubin oxidase는 $ethanol(40{\sim}80%)$ 추출 및 2회의 Sephadex G-200 column chromatography로 약 70배 정제하였으며 회수율은 12%였다. 이 효소는 분자량이 약 53,000 dalton이었으며 $40^{\circ}C$, pH 8.5에서 최대의 활성을 보였고 pH 6에서 10까지의 넓은 범위와 $40^{\circ}C$ 이하에서 안정하였다. 또 효소의 활성이 $Mg^{2+}$에 의해서 증가하였으며 $Ag^+,\;Hg^{2+},\;Mn^{2+},\;Pb^{2+}$, p-CMB, iodoacetate 및 SDS에 의해서 저해되었다. 그리고 이 효소는 bilirubin에 대한 특이성이 컸으며 bilirubin에 대한 $K_m$값은 $6.67{\mu}M$이였다.

A bilirubin oxidase produced by Penicillium sp. strain LAM 91-89 was purified and partially characterized. The enzyme was purified about 70 folds from culture broth by ethanol precipitation, first and second Sephadex G-200 column chromatography with overall yield of 12%. The molecular weight of the enzyme was estimated to be 53,000 dalton by SDS-PAGE. The optimum pH and temperature was 8.5 and $40^{\circ}C$, respectively. The enzyme was stable in the pH range $6{\sim}10$ and below $40^{\circ}C$. Activity of the enzyme was increased by the addition of $Mg^{2+}$ but was gretly inhibited by $Ag^+,\;Hg^{2+},\;Mn^{2+},\;Pb^{2+}$, iodoacetate, p-chloromercurobenzoic acid and sodium dodecyl sulfate. Among various substrates, bilirubin was favorably reacted and $K_m$ value for bilirubin was $6.67\;{\mu}mole$.