エビ類ポリフェノールオキシダーゼの分布および性質

概要

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記事区分：原著The distribution and properties of polyphenol oxidase from shrimps Penaeus japonicus and P. monodon were investigated to increase our knowledge of the blackening of crustaceans. Enzyme activity toward catechol was detected in all tissues from both species. The hepatopancreas was found to have the highest activity of catechol oxidation, and the muscle had very low activity. The shrimp enzymes had high oxidative activity towards various diphenols. The enzymes in the hepatopancreas and epidermis of P. japonicus were most active toward catechol, but the eye and gill enzymes of P. monodon had 4-methyl catechol and 3-methyl catechol, respectively, as the best substrate. None of the enzymes oxidized 4-fert-butyl catechol. The gill enzyme from P. japonicus oxidized pyrogallol and catechol at a similar rate. Only the hepatopancreas enzyme oxidized L-dihydroxyphenylalanine and L-tyrosine. Km values for catechol of the P. japonicus enzymes were 1.9×10^3 M for the gill enzyme and 3.1×10^3 M for the hepatopancreas enzyme. The enzyme activity was inhibited in the presence of metal-chelating reagents such as sodium diethyldithiocarbamate and sodium azide. These results suggest that polyphenol oxidase from P. japonicus may be a metalloenzyme that contains copper ion. Ascorbic acid and 2-mercaptoethanol orevented colour formation in the reaction mixture.
近畿大学の論文
1992-03-15