Journal of the Korean Society of Food Culture (한국식생활문화학회지)

Korean Society of Food Culture (한국식생활문화학회)
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Purification and Characterization of Invertase in Astringent Persimmon during Sun Drying

건시제조 중 Invertase의 정제 및 그 특성

  • Lee, Byung-Ou (Department of Food Engineering, Kyungpook National University) ;
  • Moon, Kwang-Deog (Department of Food Engineering, Kyungpook National University) ;
  • Shon, Tae-Hwa (Department of Food Engineering, Kyungpook National University)
  • Published : 1990.06.30
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Abstract

This study was conducted to determine invertase activity in persimmon during the drying process and characterize the purified enzyme. As drying proceeded, invertase activity increased until 10 days and decreased gradually afterwards. Invertase in persimmon fruit was extracted with 250 mM potassium phosphate sulfate buffer at pH 7.4. The enzyme was purified by means of ammonium sulfate fractionation, column chromatography on DEAE-cellulose and gel filtration on Sephadex G-200 column. The optimal temperature of enzyme was $40^{\circ}C$ and optimal pH was 5.0 and 6.0 for sucrose and raffinose, respectively. The enzyme was stable up to $50^{\circ}C$ and pH 3-6. The Km value of the enzyme, with sucrose as a substrate, was 2.5mM. Electrophoretic pattern of purified enzyme solution showed a single band.

건시제조 중 invertase의 활성 변화를 조사하고 정제된 invertase의 효소적 특성에 관하여 실험한 바 그 결과는 다음과 같다. 건조가 진행됨에 따라 invertase의 활성은 증가하여 건조 10일째 최고 활성을 나타내었으며 그 이후는 감소하였다. 건시에서 invertase를 250 mM potassium phosphate(pH 7.4)로 추출하여 $(NH_4)_2SO_4$염석, DEAE-cellulose 및 sephadex G-200 column chromatography의 과정으로 정제한 결과 정제도는 조효소액보다 약 27배 증가되었으며 회수율은 약 11%였다. 최적 pH는 sucrose, raffinose에 대하여 각각 5.0과 6.0으로 나타났으며 최적온도는 $40^{\circ}C$였다. 열과 pH 안정성은 $50^{\circ}C$까지 그리고 pH 5 부근에서 안정하였다. Sucrose에 대한 $K_m$값은 2.5 mM이었으며, 정제된 invertase는 polyacrylamide gel 전기영동상에서 하나의 band를 나타내었다.

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