Enzymatic Characteristics of Polyphenol Oxidase from Apple (Ralls Janet)

사과(Ralls Janet) Polyphenol Oxidase의 효소학적(酵素學的) 성질(性質)

  • Chung, Ki Taek (Department of Food Technology, College of Agriculture, Kyungpook National University) ;
  • Seu, Seung Kyo (Department of Food Technology, College of Agriculture, Kyungpook National University) ;
  • Song, Hyung Ik (Department of Food Technology, College of Agriculture, Kyungpook National University)
  • 정기택 (경북대학교 농과대학 식품가공학과) ;
  • 서승교 (경북대학교 농과대학 식품가공학과) ;
  • 송형익 (경북대학교 농과대학 식품가공학과)
  • Received : 1983.09.09
  • Published : 1983.12.31

Abstract

In order to obtain elementary data of enzymatic browning of apples and apple products and to examine effectively inhibitory method of browning, we extracted polyphenol oxidase (EC 1.10.3.1) from apple (Ralls Janet) and investigated its general properties. The optimum conditions for the enzyme reaction were pH 6.0 and temperature of $30^{\circ}C$. The enzyme was very stable at pH 4.0, and at the range of pH 5.0-9.0 its activity was above 80% compared with pH 4.0. The enzyme was very stable by heating at $40^{\circ}C$ for 1 hour, and almost 50% of enzyme activity was lost by heating at $60^{\circ}C$ for 30 minutes. The polyphenol oxidase activity was enhanced by the addition of $Cu^{2+}$ and $Mn^{2+}$, respectively, meanwhile $Na^+$, $Hg^{2+}$ and $Co^{2+}$ inhibited the enzyme activity. The enzyme activity was greatly decreased in the presence of inhibitors such as cysteine, sodium metabisulfite and ascorbic acid. The polyphenol oxidase greatly catalyzed the oxidation of o-diphenols such as chlorogenic acid and catechol, which suggests that main substrate of polyphenol oxidase is o-diphenol compounds.

사과 및 그 가공품의 효소적갈변(酵素的褐變)에 대한 기초적(基礎的) 자료(資料)를 얻고 나아가서 그 방지책(防止策)을 조사(調査)하는 목적으로 국광으로 부터 polyphenol oxidase(EC 1.10.3.1)를 추출(抽出)하여 그 일반적(一般的) 성질(性質)을 검토(檢討)하였다. 국광 polyphenol oxidase의 반응최적(最適) pH는 6.0이었으며 최적(最適) 반응온도(反應溫度)는 $30^{\circ}C$였다. 본효소(本酵素) pH 4.0에서 가장 안정성(安定性)이 높았으며, pH 5.0~9.0에서도 80% 이상(以上)의 활성(活性)을 나타내었다. 열(熱)에 대한 안정성(安定性)은 $40^{\circ}C$ 1시간(時間) 처리(處理)조건에서도 극히 안정(安定)하였으며 $60^{\circ}C$에서 30분(分) 처리(處理)로 효소(酵素) 활성(活性)이 50% 감소(減少)되었다. $Cu^{2+}$, $Fe^{3+}$, $Mg^{2+}$, $Mn^{2+}$의 첨가(添加)로 활성(活性)이 저해(沮害)되었다. 본효소(本酵素)에 대한 가장 효과적(效果的)인 저해제(沮害劑)는 cysteine, sodium, metabisulfite, ascorbate인 것으로 나타났다. 국광 polyphenol oxidase는 o-diphenol인 chlorogenic acid와 catechol을 크게 산화(酸化)시키는 것으로 보아 o-diphenol화합물(化合物)이 주(主) 기질(基質)인 것으로 생각되었다.

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