• 한국육종학회지
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• 제43권5호
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• pp.470-478
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• 2011

밀가루 및 국수 면대의 색깔 변화에 영향을 미치는 요인을 분석하여 소비자가 선호하는 밝은 색택의 밀가루 및 국수 제조에 적합한 품종의 육성에 유용한 간편 분석법을 확립하고자 본 연구를 수행하였다. 국산밀 25 품종을 이용하여 종실 및 밀가루 특성과 저장기간 동안 국수 면대의 밝기 변화를 조사하였다. 종실의 PPO 활성은 천립중이 낮을수록, 종실 회분과 단백질 함량이 낮을수록 낮은 경향을 나타내었다. 종실의 PPO 활성은 총 폴리페놀 함량($r=0.609^{**}$), 철 함량($r=0.655^{**}$) 과 정의 상관을 나타내었다. 단백질 함량, 총 폴리페놀 함량, 철 함량 및 밀가루 색 밝기 등의 특성이 종실의 PPO 활성과 관련이 있었으며, 종실의 PPO 활성이 높은 품종일수록 국수 면대의 저장 기간 중에 면대 색이 보다 빠르고 어둡게 변색되었다. 국수 면대 색이 밝은 국내 밀 품종 개발을 위해서는 평가 방법이 용이하고 밀가루 및 국수 색깔과 높은 상관이 있는 종실의 PPO 활성을 육종 초기 세대에 평가해야 할 것으로 생각된다.

• 약학회지
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• 제48권6호
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• pp.384-390
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• 2004

Polyphenol oxidase-catalyzed oxidation of substrates (t-butylcatechol, 4-methylcatechol, chlorogenic acid, caffeic acid and pyrocatechol) were performed in the Ph range 4~8. Co ncentrations of substrate's major oxidation products were monitored by high performance liquid chromatograph. The nature and amounts of products formed were highly pH dependent. They also were ifluenced by kinds of substrates. Major oxidation product of 4-methylcatechol appeared the maxium value at pH 5, them of chlorogenic acid, caffeic acid and pyrocatechol at pH 6.0 and that of t-butylcatechol at pH 5~7. Time-dependent PPO activity was determined at $4^{\circ}C\;and\;30^{\circ}C$. PPO extracted by phosphate buffer containing triton X-114 (t-PPO) was more stable than PPO by phosphate buffer (b-PPO). The result of electrophoresis, at first PPO was showed only a band at 48 kd. After 1~3 days a partial degrade band was appeared in b-PPO and three partial degrade bands in t-PPO. No activity band was appeared in PPOs at $30^{\circ}C$ and b-PPO at $4^{\circ}C$ after 4 days. And a band (37 kDa) in t-PPO was remained finally and disappered. PPO from Perillae leaves has two activity bands at 48 and 37 kDa in previous paper. It was supposed that PPO in the leaves of Perilla frutescens was a protein having one molecular weight as 48 kDa. And 37 kDa protein, relatively proteolysis-resistant, was a proteolyzed form of a major form.

• Applied Biological Chemistry
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• 제38권4호
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• pp.345-352
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• 1995

진공예냉처리에 의한 표고버섯의 변색, PPO활성 및 유리아미노산 함량 변화에 미치는 영향을 조사 하였다. 저장중 예냉처리한 버섯의 경우 예냉처리하지 않은 버섯에 비하여 표면색택의 변화가 억제되어짐을 알 수 있었다. 한편 저장중 Polyphenoloxidase(PPO) 의 활성은 증가하였는데 예냉처리한 버섯의 경우 예냉처리하지 않은 버섯에 비하여 PPO 활성이 낮게 나타났고 갈변이 진행되면서 그 활성이 상대적으로 더 증가한 것으로 나타났다. 그리고 포장방법에 있어서는 PVC 랩포장한 경우가 골판지 포장한 표고버섯에 비하여 변색이 억제됨을 알 수 있었고 아울러 PPO 활성도 더 낮게 나타났다. 표고버섯의 유리아미노산 함량은 수확 직후에는 2,501 mg%였으며 그 중 glutamic acid가 가장 많았고, 저장중 유리아미노산 함량은 계속 감소하는 경향을 나타내었다. 처리구별 차이를 보면 예냉처리한 버섯의 유리아미노산 함량이 예냉처리하지 않은 버섯에 비하여 전반적으로 높게 나타났으며, 저장온도와 포장방법 그리고 기간에 따라서 상당한 변화를 보였다.

• Current Research on Agriculture and Life Sciences
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• 제9권
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• pp.51-59
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• 1991

밤과실의 가공 및 저장중 갈변기구를 규명하는 일환으로 밤에 함유된 polyphenol 화합물 및 PPO를 분리, 동정하고 PPO의 생화학적 특성에 대해 연구한 결과는 다음과 같다. 밤의 total phenol 함량은 $6.5{\mu}g/g$이었고 ferulic acid, caffeic acid, synapic acid, p-coumaric acid, gallic acid, salicylic acid 순으로 함량이 높았다. PPO를 분리, 정제하여 전기영동한 결과 단일의 단백질 및 효소활성밴드를 확인하였으며 정제된 효소의 비활성도는 260.9이고 조효소액보다 11.7배 정제되었다. PPO의 최적 pH와 온도는 각각 5.9, $45^{\circ}C$였으며 효소활성은 $80^{\circ}C$에서 15분 처리시 거의 실활되었다. 무기염의 영향을 본 결과 $Mg^{{+}{+}}$, $Ca^{{+}{+}}$, $Zn^{{+}{+}}$들은 효소활성을 증가시켰으나 $Fe^{{+}{+}}$, $K^+$, $Hg^{{+}{+}}$는 활성을 저해시켰다. 저해제로는 L-ascorbic acid, thiourea, sodium chloride, L-cysteine의 저해작용이 강했다. 밤의 PPO는 o-diphenol에 대한 강한 활성을 나타냈으며 특히 catech이에 대해 가장 강했으며 monophenol에는 활성을 나타내지 않았다. PPO의 Km값은 catechol에 대해 5mM이었다.

• Food Science and Biotechnology
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• 제14권1호
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• pp.117-122
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• 2005

Polyphenoloxidase (PPO) was extracted from Solanum tuberosum Jasim by various chromatographic methods and was subsequently purified and characterized. PPO was purified upto 78-fold from the crude extract. SDS-PAGE profile of the enzyme showed a major subunit of PPO with molecular weight of 40 kDa. The optimum pH and temperature for the maximum activity of PPO was 6.5 and $25^{\circ}C$, respectively. The enzyme was found to be quite stable between 10 and $40^{\circ}C$, whereas it was almost inactivated at $70^{\circ}C$ when incubated for 30 min. Substrate specificity study indicated that catechol was the most suitable substrate for PPO isolated from purple-fleshed potato with a $K_m$ value of 21.1 mM. The most effective inhibitor was ascorbic acid, followed by L-cysteine, citric acid, EDTA, and boric acid. Studies on the effect of metal ion on PPO activity showed that magnesium and copper were inhibitory, while iron and zinc ions increased the activity of PPO.

• 한국식품영양과학회지
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• 제17권4호
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• pp.348-357
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• 1988

갈변반응에 관여하는 polyphenol oxidase(PPO : EC 1.10.3.1)를 한국산 고구마(Ipomoea batatas, val : Hong-mi)로부터 추출하여 ammoniun sulfate 분획 및 DEAE-cellulose column chromatography법에 의하여 정제한 결과, 효소활동도는 23.1배였으며 enzyme activity 수율은 41.5%이었다. 이 효소는 일반 전기 영동법에 의하여 8개의 isozymes 으로, 또한 isolectric focusing에 의하여 pI가 각각 다른 12개의 isozymes으로 분리되었고 그 pI의 범위는 3.2-9.6이었으며, Isoelectric focusing에 의하여 분리된 각 isozyme의 specific activity는 6,000-46,700U/mg protein의 범위에 있었다. 고구마 중의 PPO는 $65^{\circ}C$이하에서는 안정하였으며 $65^{\circ}C$ 에서는 1분 가열에 의하여 약 50%의 효소활성이 상실되었고, pH optimum은 6.0-6.5이었다. o-diphenol이 이 효소의 가장 좋은 기질로서, 이 효소는 o-diphenolase임이 확인되었고, catechol에 대한 Km치는 6.7mM로 나타났다. 또한 이 효소에 대한 저해작용은 dithiothreitol, cysteine 및 ascorbic acid 순으로 크게 나타났다.

• Journal of Ginseng Research
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• 제37권1호
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• pp.117-123
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• 2013

Polyphenol oxidase (PPO) was purified from fresh ginseng roots using acetone precipitation, carboxymethyl (CM)-Sepharose chromatography, and phenyl-Sepharose chromatography. Two isoenzymes (PPO 1 and PPO 2) were separated using an ion-exchange column with CM-Sepharose. PPO 1 was purified up to 13.2-fold with a 22.6% yield. PPO 2 bound to CM-Sepharose, eluted with NaCl, and was purified up to 22.5-fold with a 17.4% yield. PPO 2 was further chromatographed on phenyl-Sepharose. The molecular weight of the purified PPO 2 from fresh ginseng was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and was about 40 kDa. The optimum temperature and pH were $20^{\circ}C$ and 7.0, respectively, using catechol as a substrate. Pyrogallol showed the highest substrate specificity. The effect of a PPO inhibitor showed that its activity increased slightly in the presence of a low concentration of citric acid. High concentrations of acidic compounds and sulfite agents significantly inhibited purified ginseng PPO 2.

• 생약학회지
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• 제30권3호
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• pp.306-313
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• 1999

Polyphenol Oxidase(PPO) was purified from an extract of Ginkgo biloba leaves by ammonium sulfate fractionation followed by sephadex G-150 column chromatography, which resulted in a 18-fold increase in specific activity. The enzyme was most active at pH 8.5 and the temperature optimum for the PPO catechol oxidation reaction was $45^{\circ}C$. Heat inactivation studies showed that heating for 7, 9 and 48 min, at 80, 70 and $60^{\circ}C$ respectively caused a 50% loss in enzymatic activity and that the enzyme was completely inactivated after heat treatment at $90^{\circ}C$ for 60 min. Km values of the PPO for catechol, hydroquinone and 4-methylcatechol derived from Lineweaver-Burk plots were $6.06\;{\times}\;10^{-4}M,\;1.02\;{\times}\;10^{-3}M,\;1.41\;{\times}\;10^{-3}M$ respectively. Of the substrates tested, 4-methylcatechol was oxidized most readily and the enzyme did not oxidize monophenols. The enzyme datalyzed browning reaction was completely inhibited in the presence of reducing reagents, namely ascorbic acid, cysteine, glutathione, 2-mercaptoethanol, potassium metabisulfite at 0.5 mM level. Sodium chloride showed very little inhibition effect on Ginkgo biloba leaves PPO. Lineweaver-Burk analysis of inhibition data revealed that the inhibition by cysteine, 2-mercaptoethanol, potassium cyanide was competitive with ki values of $1.1\;{\times}\;10^{-5}M,\;2.4\;{\times}\;10^{-5}M,\;8\;{\times}\;10^{-5}M$, respectively. Among the divalent cations, $Cu^{2+}ion$ was a strong activator on PPO and $Mn^{2+}ion$ was little or no effect on PPO activity $Ni^{2+}ion$ was an inhibitor on PPO.

• 생약학회지
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• 제22권2호
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• pp.101-111
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• 1991

Polyphenol oxidase(PPO) was purified from an extract of Puerariae Radix by ammonium sulfate fractionation followed by Sephadex G-150 column chromatography, which resulted in a 56-fold increase in specific activity. The enzyme was optimum of pH 6.5. The optimum temperature of enzymic reaction was about $40^{\circ}$. The enzyme was thermostable with a half-life equal to 32 min at $70^{\circ}$. Km values of the PPO for catechol and pyrogallol from Lineweaver Burk plots were $1.3{\times}10^{-2}M$, $1.16{\times}10^{-2}M$, respectively. The substrate specificity of the Puerariae Radix PPO showed high affinity toward pyrogallol. Reducing reagents such as cysteine, potassium metabisulfite, ascorbic acid, 2-mercaptoethanol completely inhibited the PPO activity at $10^{-2}M$ level. Linewear-Burk analysis of inhibition data revealed that the inhibition by cysteine, 2-mercaptoethanol, 4-nitrocatechol, potassium cyanide was competitive with Ki values of $4.3{\times10^{-2}M,\;0.73{\times}10^{-6}M,\;6.9{\times}10^{-6}M,\;6.4{\times}10^{-7}M$, respectively. The browning reaction by PPO was observed to decrease temporarily with the addition of sodium diethyl dithiocarbamate, a well known copper chelating agent. Among the divalent cations, $Cu^{2+}$ ion was strong activator on PPO and $Mn^{2+},\;Co^{2+}$ ions was effect on PPO activity. $Zn^{2+},\;Mg^{2+}$ ions was inhibitor on PPO.

• 생명과학회지
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• 제22권11호
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• pp.1451-1455
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• 2012

다양한 아미노산과 당을 $90^{\circ}C$에서 반응시켜 생성한 마이얄반응 생성물(Maillard reaction product)은 쑥갓에서 추출한 폴리페놀산화효소(polyphenol Oxidase, PPO)를 강하게 저해하였다. 글리신(glycine)과 포도당을 함유한 반응물으로부터 MRP의 생성은 $90^{\circ}C$에서 반응시간에 따라 직선적으로 증가하였으나 글리신과 포도당의 양은 상대적으로 감소하였다. 반응액에서 MRP의 증가함에 따라 반응액은 쑥갓 PPO활성을 비례적으로 강하게 저해하였다. 실험에 사용한 아미노산과 당중에서 글루타민과 자일로스를 아미노산과 당으로 이용했을 경우에 생성된 MRP가 쑥갓 PPO의 활성에 강한 저해제로 작용하였다. 카테콜을 기질로 사용한 쑥갓 PPO의 마이클레스 상수(Michaelis Menten constant)는 22.0 mM이었으며, MRP는 쑥갓 PPO의 비경쟁적 저해제로 작용하였다.