Isolation and Characteristic of Polyphenol Oxidase from Jerusalem Artichoke Tuber

돼지감자 Polyphenol Oxidase의 분리와 특성

  • Park, Eun-Bae (Department of Food Science, Seoul Woman's University) ;
  • Lee, Jun-Sik (Department of Bioengineering, KAIST) ;
  • Choi, Eon-Ho (Department of Food Science, Seoul Woman's University)
  • 박은배 (서울여자대학교 식품과학과) ;
  • 이준식 (한국과학원 생물공학과) ;
  • 최언호 (서울여자대학교 식품과학과)
  • Published : 1991.08.01

Abstract

Polyphenol oxidase from Jerusalem artichoke(Helianthus tuberosus L.) tubers was partially purified by precipitation with ammonium sulfate, followed by gel filtration on Sephadex G-100. The enzyme showed maximal activity at pH 6.5 and $4^{\circ}C$. Kinetic studies indicated $K_{m}$ value of 3 mM for catechol and activation energy of 72.6 kcal/mole. As for substrate specificity of polyphenol oxidase the enzyme showed high affinity towards diphenol compounds, but not towards monophenols. The enzamatic browning was completely inhibited at 1 mM concentration of L-ascorbic acid, sodium hydrosulfite and L-cystein(HCl). The activity of polyphenol oxidase in 0.1 M potassium phosphate buffer(pH 6.5) was fairly stable for a week at $4^{\circ}C$, while it decreased remarkably at $25^{\circ}C$.

Keywords

polyphenol oxidase;Jerusalem artichoke;inhibitor;enzyme inactivation