• Current Research on Agriculture and Life Sciences
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• 제1권
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• pp.141-150
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• 1983

사과 Fuji와 국광을 저온(低溫) 상태하(狀態下)에서 저장방법(貯藏方法)을 달리하였을 때, 내부갈변(內部褐變) 및 PPO.의 변화(變化)에 대하여 조사한 결과는 다음과 같다. 1. P.E film저장(貯藏)에 있어서 내부갈변(內部褐變) 정도(程度)는 11월(月)에 수확(收穫)한 Fuji가 10월(月)에 수확(收穫)한 Fuji보다 많았고, 0.09mm 2%구(區)에서 가장 많이 나타났고 0.06mm 2%구(區), 0.06mm 2%구(區)의 순(順)이었으며 $CO_2$를 완전히 제거(除去)한 감압저장(減壓貯藏)에서는 내부갈변(內部褐變)을 볼 수 없었다. 2. P.E film저장중(貯藏中) Fuji의 PPO. activity 및 PPO. specific activity는 11월(月) 수확(收穫)이 10월(月) 수확(收穫)에 비해 높았으며, 0.09mm의 2%구(區)가 0.06mm구(區)보다 높았고, 저장중(貯藏中) 증가(增加)하는 경향이었고, $CO_2$를 완전히 제거(除去)한 감압저장(減壓貯藏) 동안 Fuji의 PPO. activity는 변화(變化)가 거의 없었으나 PPO. specific activity는 계속 감소(減少)하였다. 3. 국광의 PPO. activity는 Fuji에 비해 상당히 높았고 저장중(貯藏中) PPO. activity 및 specific activity는 저장(貯藏) 초기(初期)와 거의 차이(差異)가 없었다. 4. 이상(以上)으로 미루어 Fuji의 내부갈변(內附褐變)은 저온장해(低溫障害)보다는 $CO_2$장해(障害)로 보이며 품종간(品種間)의 PPO. activity의 정도(程度)와 내부갈변(內附褐變)의 관련(關聯)은 찾을 수 없는 것 같다. 그러나 Fuji의 경우 PPO. activity증대(增大)는 $CO_2$의 영향(影響)을 받은 것으로 보이며 내부갈변(內部褐變)과 어느정도 관련(關聯)이 있는 것 같다.

• 한국작물학회지
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• 제53권2호
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• pp.187-195
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• 2008

Polyphenol oxidase (PPO) is implicated in discoloration of white salted noodles and other wheat based foods. PPO activity was evaluated to determine the effect on discoloration of noodle dough sheets prepared from 25 Korean wheat flours during storage and to screen experimental lines with low PPO activity in 52 Korean wheats. PPO activity was assayed with whole-seed and performed with L-dihydroxyphenylalanine (L-DOPA) as substrates. Absorbance by L-DOPA assay of 25 Korean wheats was from 0.285 to 1.368 at 475 nm. PPO activity was significantly related with grain characteristics, including 1000-kernel weight and grain colors. In flour characteristics, PPO activity positively correlated with ash and protein content (r = 0.658, P < 0.001 and r = 0.424, P < 0.05, respectively) and negatively correlated with $L^*$ value of flour (r = 0.412, P < 0.05). In the changes of color of noodle dough sheet, $L^*$ and $b^*$ values consistently decreased and $a^*$ value increased during storage. PPO activity negatively correlated with $L^*$ value of noodle dough sheet during storage (r = 0.566, P < 0.01 at 2 hr, r = 0.547, P < 0.01 at 24 hr, and r = 0.509, P < 0.01 at 48 hr). But, no significant relationship was found in between PPO activity, $a^*$ and $b^*$ values during storage. The 52 Korean wheat lines examined in this study were divided into 3 different groups, low (< 0.500), medium (0.501-0.999) and high level (> 1.000), on the basis of the level of PPO activity. Twenty two Korean wheat lines showed low level of PPO activity and Suwon 252, 277 and 280 showed lower PPO activity (< 0.200) than others.

• 약학회지
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• 제40권1호
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• pp.65-71
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• 1996

Characterization of Polyphenol oxidase (PPO) in Perillae Folium, particullarly inhibitor studies were investigated. This enzyme was stable at pH 5.0 and the residual activity of PPO at ${\geq}$ ph 5.5 was estimated to be very low. PPO activity was decreased slightly by adding amino acid with catechol as a substrate, particullary PPO activity was inhibited markedly by cystein, histidine, lysine and arginine. In the absorption spectra of the product formed when catechol was oxidized by PPO, with a ${\lambda}_{max}$ at 410nm, the peak shifted toward ${\lambda}_{max}$ 520nm by addition of L-proline. At relatively low concentrations($10^{-3}M$), sulfite and dithiothreithol completely inhibited PPO activity. Inhibition of PPO activity by amino acids and inhibitors increased or decreased depending on the pH used to measure it.

• 한국환경과학회지
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• 제8권6호
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• pp.669-676
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• 1999

The effects of wounding and jasmonic acid(JA) on polyphenol oxidase(PPO) in tomato(Lycopersicon esculentum Mill.) seedlings were investigated. PPO was strongly induced by wounding or JA, and the response was also shown to be systemically induced by wounding. Mechanical wounding in cotyledon or leaf produced a signal that caused the concentration of PPO to increase in the unwounded cotyledon, in the first leaves but not in the second leaves. Severity of wounding and light intensity also affected wound induced change in PPO activity, JA showed a stimulatory effect on the loss of chlorophyll and the rapid increase in PPO activity. The PPO was clearly more active in the wounded leaves than in controls. The potency and specificity of the JA indicate a close relationship between JA and wound-induced changes in PPO in tomato species. JA and abscisic acid(ABA) acted similarly on both unwounded and wounded leaves, but the amount of PPO in the wounded leaves was always more than the respective controls. The highest increase in PPO activity occurred in woundand JA-induced leaves of seedlings kept under bright lighting. Benzyladenine(BA) completely abolished JA- and ABA-induced PPO activity. The results suggest that JA-induced PPO activity is due to de novo PPO synthesis. Histochemical tests for PPO in stems of wound- and JA -treated tomato plants indicate that PPO was localized primarily, in the. outer .cortex . and xylem parenchyma. It is concluded that exogenously applied JA acts as stress agents and PPO may be a component of the inducible anti-hervivore defense response.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권4호
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• pp.231-240
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• 2000

Effects of Jasmonic Acid and Wounding on Polyphenol Oxidase Activity in Senescing Tomato Leaves The effects of jasmonic acid(JA) and wounding on polyphenol oxidase(PPO) during leaf senescence was investigated by measuring the PPO activity in detached tomato(Lycopersicon esculentum Mill.) leaves of two-week-old seedlings. The PPO activity in the detached senescing leaves increased significantly in the dark. The leaf segments responded to the application of JA with accelerated senescence, as indicated by the loss of chlorophyll and rapid increase in the PPO activity. The senescence-promoting action of JA differed in the light and dark. Wounding the detached senescing leaves by scraping surface segments or making punctures with needles considerably delayed the loss of chlorophyll and had a significant effect on the PPO activity, the amounts of which were roughly proportional to the intensity of the wounding. In the dark, the combination of wounding plus JA resulted in stable levels of chlorophyll and PPO. JA and ABA acted similarly in both unwounded and wounded leaves, however, the amount of chlorophyll and PPO in the wounded segments was always higher than in the respective controls. JA was found to eliminate the senescence-retarding action of benzyladenine. In a histochemical localization test, the PPO activity was found to be localized in the cell walls of the parenchyma tissue, thereby indicating moderate cytoplasmic reactions. In the JA-treated plants, the PPO activity was intense in the cells of the cortex and phloem parenchyma. Accordingly, based on these observations it would appear that PPO is a component of a defense response maker, whereas JA plays an integral role in the intracellular signal transduction involved in inducible defense mechanisms.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.142.3-143
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• 2003

Time-dependent PPO activity was determined at $4^\times$C and $30^\times$C. The result of activity determination, PPO extracted by phosphate buffer containing triton x-1l4(tPPO) was more stable than PPO by phosphate buffer(bPPO). The result of electrophoresis, at first a band was appeared at 48kd. After 1-3days a partial degrade band was appeared in bPPO and three partial degrade bands in tPPO. No activity band was appeared in PPOs at $30^\times$C and bPPO at $4^\times$C after 4 days. (omitted)

• Current Research on Agriculture and Life Sciences
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• 제4권
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• pp.55-64
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• 1986

배과실(果實)의 PPO를 분리(分離) 정제(精製)한 후(後) 그 특성(特性)을 조사(調査)한 결과(結果)는 다음과 같다. 조효소액(粗酵素液)을 전기영동한 결과 2개의 활성분리대(活性分離帶)가 관찰(觀察)되었으며, 이 조효소액(粗酵素液)을 acetone 심몰(沈沒)과 DEAE-cellulose chromatography로 부분정제(部分精製)한 결과 PPO A 분획(分劃)과 PPO B 분획(分劃)을 얻었다. 각 구분을 전기영동(電氣泳動)한 결과 PPO A, B 각각 Rm치가 0.58, 0.68인 단일 활성분리대(活性分離帶)가 관찰(觀察)되었다. PPO A와 PPO B의 최종 정제도(精製度)는 각각 7.8와 8.7배(倍)였다. PPO A의 최적(最適) pH와 온도(溫度)는 pH 7, $33^{\circ}C$인 반면 PPO B의 최적(最適) pH와 온도(溫度)는 pH 4.2, $30^{\circ}C$로 나타났다. PPO A, B의 열(熱) 안정성(安定性)은 $60^{\circ}C$ 이상(以上)의 온도(溫度)에서는 급격히 활성(活性)이 감소했으며 PPO B보다 PPO A가 더 안전(安定)하였다. 배의 두 PPO는 o-diphenol에 강한 활성을 나타냈으며 특히 PPO A는 catechol에 PPO B는 chlorogenic acid에 활성이 강했다. 또한 PPO A는 pyrogallol에도 활성을 나타냈다. 그러나 두 PPO는 m-diphenol, p-diphenol과 monophenol에는 활성(活性)을 나타내지 않았다. 무기염(無機鹽)의 영향(影響)을 본 결과(結果)는 10mM농도(濃度)에서 $Zn^{{+}{+}}$은 PPO A의 활성(活性)을 증가(增加)시켰으나 $Fe^{{+}{+}}$는 저해(沮害)했고 반면 $Fe^{{+}{+}}$, $Zn^{{+}{+}}$는 PPO B는 활성(活性)을 증가(增加)시켰으나 $K^+$, $Mg^{{+}{+}}$, $Ca^{{+}{+}}$, $Hg^{{+}{+}}$는 저해(沮害)했다. $Cu^{{+}{+}}$는 저농도(低濃度)에서는 효소(酵素)를 활성화(活性化)시켰으나 10mM의 고농도(高濃度)에서는 저해작용(沮害作用)을 했다. 저해제(沮害劑)의 작용(作用)을 조사(調査)한 결과(結果), L-ascorbic acid, L-cysteine, thiourea 등이 저해작용(沮害作用)이 강했다. PPO A와 PPO B의 catechol에 대한 Km치는 각각 20mM과 14.3mM이었다.

• 한국식품영양과학회지
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• 제33권6호
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• pp.1013-1016
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• 2004

토란으로부터 polyphenol oxidase를 추출하여 Maillard reation products(MRPs)가 토란 PPO에 미치는 영향을 조사하였다. 토란 PPO에 대한 MRPs의 저해 효과는 사용한 기질이 (+)-catechin, catechol인 경우에 높게 나타났다. 그리고 MRPs의 토란 PPO 저해 효과는 당의 종류를 달리하여 생성한 MRPs 중에서 fructose와 glucose로 제조한 MRPs의 첨가시 가장 높았으며, glycine과 glucose의 농도가 높아질수록 저해 효과가 증가하였다. 반응 시간에 따른 MRPs의 저해 효과를 조사한 결과, 반응 시간이 길어질수록 MRPs의 변색 정도가 높아졌으며, 이에 따라서 토란 PPO에 대한 저해 효과도 증가하였다.

• 한국식품영양과학회지
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• 제30권6호
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• pp.1301-1304
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• 2001

본 연구는 사과의 구취억제인자를 구명하기 위한 기초자료로써 사과 추출물의 획분에 따른 사과에서 추출한 PPO의 methyl mercaptan에 대한 구취 억제활성을 조사하였다. 사과를 탁즙하여 구취 억 제 활성 을 측정 해 본 결과, 사과 고형 분의 농도가 증가함에 따라 구취억제활성이 증가하는 경향을 나타내었다. 사과의 저분자획분에 PPO를 첨가한 경우, 저분자 획분의 농도증가 및 반응시간에 따른 methyl mercaptan에 대한 구취억제활성이 증가하는 경향을 나타내었다. 이상의 결과는 사과에서 추출한 PP7에 의한 갈변반응의 중간체로 생성되는 o-quinone이 methy mercaptan과 결합하여 meth- yl mercaptan을 비 휘 발성으로 전환시켜 구취억제활성을 나타내는 것으로 생각된다

• 한국식생활문화학회지
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• 제10권2호
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• pp.89-95
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• 1995

Three potato cultivars, Sumi,Daejima and Namjak, were prepared as slices. They were dipped in distilled water for 20 seconds. The potato slices were packed in polyethylene bags and stored at $5^{\circ}C$. Browning degree, total phenol and chlorogenic acid contents and polyphenol oxidase (PPO) activity were measured. And the correlation analysis of browning parameters were conducted. The results were as follows. There were increase in browning degree, phenolic content and PPO activity during cold storage of potato slices with different cultivars. Among three cultivars, Sumi showed the highest browning degree, phenolic content and PPO activity and also showed the highest % increse of browning and PPO activity during cold storage. On the contrary, Daejima was the lowest. But Daejima showed the highest % increase in phenolic contents during cold storage. With Sumi, browning degree was significantly correlated with PPO activity and phenolic contents (p<0.05). With Daejima and Namjak, a significant correlation was found between browning degree and PPO activity (p<0.05). From the above results, enzymatic browning reactions of potato slices and factors affecting them were dependent on cultivar. Among the tested three cultivars, Daejima showed the lowest browning degree during cold storage and thus seems to be desirable for minimal processing.