ズワイガニ・カテコ-ルオキシダ-ゼの特性〔英文〕

概要

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A catechol oxidase (EC 1.10.3.1) was extracted from the gills of the snow crab, Chionoecetes opilio, and purified by ammonium sulfate fractionation, ion exchange chromatography on DEAE-cellulose, and gel filtration on Sepharose 6B. Two active components (E-I and E-II) were obtained. E-II was unstable and lost its activity rapidly; therefore, only E-I was purified. The enzyme was purified about 16-fold, the recovery of enzyme activity was 20%. The enzyme was most active at .p.H 6.2 for catechol. The molecular weight of the enzyme was estimated to be about 380, 000 by gel filtration; its isoelectric point was found to be .p.H 5.0 to 5.2. The activity was inhibited by potassium cyanide, sodium azide, and sodium diethyldithiocarbamate, which combines with copper. The enzyme was active toward various diphenols and trihydroxy phenols, and also toward oxidized monophenols such as o-, m-, p-aminophenol, L-tyrosine and its derivatives. The Km value for catechol was 4.1×10-2M.