ニホンナシのポリフェノール酸化酵素の精製とその性質わよびL-エピカテキン酸化酵素活性

概要

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Three polythenoloxidases (F-I, F-II and F-III) from the immature fruit of the Japanese pear (Pyrus serotina Rehd. var. culta) were separated by ion exchange chromatography on DEAE-Toyopearl. F-I fraction was purified to electrophoretic homogeneity using Sephadex G-100 gel filtration. The purification rate was 93-fold. The molecular weight of F-I was estimated to be about 56,000 by gel filtration. F-I oxidized chlorogenic acid, L-epicatechin and other o-diphenols but did not oxidize monophenols, m-and p-diphenols. The optimum pH of F-I was 4.2 when o-diphenols such as chlorogenic acid and catechol were employed as substrates. F-I was found to be acid polyphenoloxidase with an active pH range from 3 to 5. The enzyme was considerably stable at relatively high temperature and was inhibited by potassium cyanide, sodium fluoride and some chlorides. While F-II and F-III showed optimum activity for L-epicatechin and catechol at pH 7〜7.5 and for chlorogenic acid at pH 4,their L-epicatechinoxidase activity was extremely high compared, with other polyphenoloxidase activities.
社団法人日本農芸化学会の論文