• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.111-116
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• 1996

Polyphenol oxidase(PPO) isolated from the crude extract of ascidian, Halocynthia roretzi, showed higher affinity for catechol than tyrosine or DL-DOPA. Successful enzyme assay could be performed at $25^{\circ}C$, 10min. by mixing 0.2ml of crude enzyme extract with 2.8ml of 0.13M catechol in 0.1M sodium phosphate buffer(pH 6.4). The specific activity of PPO which had been purified with a combination of ammonium sulfate treatment, ion exchange chromatography on DEAE-cellulose, and gel filtration on Sepharose 6B was 13-fold disc gel electrophoresis. The activity of PPO was stable from pH 5.0 to 8.0 and showed the peak activity at pH 6.4 .The optimum reaction temperature for PPO oxidation on catechol was 35$^{\circ}C$ and those enzyme were heat stable up to 4$0^{\circ}C$. Molecular weigth of the enzyme was estimated about 170kDa. One molecule was found to be composed of gour subunits. Two of them had molecular weigh of 55kDa and the others 30kDa. The {TEX}$K_{m}${/TEX} values, {TEX}$V_{max}${/TEX} and catalytic efficiency({TEX}$V_{max}${/TEX}/{TEX}$K_{m}${/TEX}) for catechol were 0.12mM, 2.5mM/liter/min. and {TEX}$0.18min^{-1}${/TEX} respectively. The substrate affinity and electrophorectic pattern suggested that the enzyme of ascidian was considered to be not tyosine but catechol oxidase.

• Preventive Nutrition and Food Science
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• 제6권2호
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• pp.107-111
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• 2001

Physical and chemical characteristics of four white-and one yellow-fleshed peach cultivars were compared at optimum maturity stage. In addition, differences of phenolic composition, polyphenol oxidase (PPO) activities and PPO isozyme patterns in two peach types were also investigated. There are no significant differences in firmness and color values between two peach types, except for "Yumyung", a white-fleshed peach with the highest firmness, and "Hwangdo", a yellow-fleshed peach with the highest yellowness (b)* value. In general, the soluble solid/titratable acidity ratios, ascorbic acid and total phenolic contents were significantly higher for white-fleshed peaches than those for yellow-fleshed peach (p<0.05). Three major phenolic compounds, catechin, neochlorogenic acid and chlorogenic acid, were found in both the white-and yellow-fleshed peaches. Among them, catechin was the predominant phenolic compound in the white-fleshed peaches, followed by neochlorogenic acid, and chlorogenic acid. Meanwhile, neochlorogenic acid was present in the highest level of the yellow-fleshed peach, but levels of two other phenolic compounds were lower. PPO activities of the white-fleshed peaches were generally higher than that of the yellow-fleshed peach, with the one major band and two minor bands, and there were no big differences in PPO isozyme patterns between two different peach cultivars.

• 한국식품조리과학회지
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• 제13권4호
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• pp.390-395
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• 1997

보리가루, 엿기름, 찹쌀가루의 수용성 추출물과 농축액이 효소적 갈변에 대한 억제 효과가 있는지를 PPO 활성에 대한 저해효과를 통하여 알아보았으며, PPO에 대한 저해효과가 가장 크게 나타난 엿기름 농축액의 갈변 정도와 환원성을 측정하고 이들 성질과 PPO활성에 대한 저해효과와의 상관관계도 조사하였다. 나아가 사과 슬라이스를 엿기름 농축액에 침지한 후 냉장하고 냉장 중 사과 슬라이스의 조직감과 갈변 정도를 조사한 결과는 다음과 같다. PPO에 대한 억제 효과는 엿기름 농축액이 가장 크게 나타났다. 엿기름 농축액은 가열 시간에 따라 당도, 갈변정도와 환원성은 증가하는 경향을 나타냈으며, PPO 활성은 감소하는 경향을 보였다 이러한 변화는 가열 60분까지는 서서히 변화하였으나 70분 이후에는 급격한 변화를 나타내었다. 또한 가열시간에 따라 엿기름 농축액의 pH는 감소하였다. 한편 엿기름 농축액에 침지한 사과 슬라이스의 냉장 저장중의 갈변정도는 6.9%로, 조직감의 변화는 14.3%로 가장 낮았다. 따라서 엿기름 농축액이 사과 슬라이스의 갈변 억제와 조직감 유지에 효과가 있는 것으로 나타났다.

• 한국작물학회지
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• 제45권1호
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• pp.38-43
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• 2000

The environment in which a given genotype is grown may influence its grain quality characteristics. When varieties are $\times$ evaluated over numerous environments, a variety environment interaction usually is observed, but the relative magnitude of environmental(E), genetic(G), and G $\times$ E effects on quality is unclear. In order to determine relative contribution of genotype, environment, and G $\times$ E interaction to the variations observed in grain quality characteristics, 18 Korean wheat cultivars and experimental lines were evaluated in two environments in 1998 and 1999. Correlation coefficients between grain quality and agronomic characteristics were also estimated. The analysis of variance for the optical density obtained by reaction bet- ween gliadin and anti-gliadin polyclonal antibody (AGPab) indicated that gliadin content measured by Enzyme-Linked Immunosorbent Assay(ELISA) was significantly in- fluenced by environment and cultivar differences. The significant differences of year and year $\times$ location were also found. The ratio of the variances associated with environmental effects to the variances associated with genetic effect gave relatively greater influence of environmental factor on gliadin content. The different protein content from same genotype grown in different environment might be associated with degree of storage protein accumulations. Significant relationships between ELISA and protein content, yield, ten spike weight, and ten spike number were detected. Polyphenol oxidase (PPO) activity was significantly influenced by year, location, cultivar and year $\times$ location. The variance in grain PPO activities among growing years appeared larger than the variation produced by the cultivar examined. This suggested that the growing environment contributed more to variability in grain PPO concentration.

• Current Research on Agriculture and Life Sciences
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• 제33권2호
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• pp.65-68
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• 2015

Hunter's color value "a" in dried-persimmon of table and full ripe fruit was higher than that in unripe fruit. In case of soluble solid content, full ripe fruit was $50^{\circ}Brix$, the highest degree, while unripe fruit was $40^{\circ}Brix$, the lowest degree. PPO activation of unripe fruit was 4.7, which was higher than table-ripe fruit (0.7) and full ripe (1.0). Polyphenol oxidase activation remained even while drying, but there was no difference in PPO activation degree as drying period increased. Total phenol content of unripe fruit was 101.4, which was higher than table-ripe fruit (57.5) and full ripe fruit (67.4). Total phenol content level increased as drying period increased, which was based on fresh weight. Hardness of unripe and table ripe fruit continued to decrease until three weeks during softening. After that, hardness was high and it started drying. However, in full ripe fruit, hardness increased after two weeks and softening was fast during the drying period, and its weight reduction rate was lower than that of unripe and table ripe fruit.

• Food Science and Biotechnology
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• 제15권2호
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• pp.177-182
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• 2006

Polyphenol oxidase (PPO) was isolated from the flesh of Fuji apples by DEAE-Cellulose, ammonium sulfate precipitation, phenyl-Sepharose CL-4B, and Sephdex G-100 chromatography. The molecular mass of the purified PPO was estimated to be 40 kDa by SDS polyacrylamide gel electrophoresis. With regard to substrate specificity, maximum activity was achieved with chlorogenic acid as substrate, followed by catechin and catechol whereas, there was no detectable activity with hydroquinic acid, resorcinol, or tyrosine as substrate. The optimum pH and temperature with catechol as substrate were 6.5 and $35^{\circ}C$, respectively. The enzyme was most stable at pH 6.0 and unstable at acidic pH. The enzyme was stable when it was heated to $45^{\circ}C$ but heating at $50^{\circ}C$ for more than 30 min caused 50% loss of activity. Reduced $ZnSO_4$, L-cystein, epigallocatechin-3-o-gallate (EGCG), and gallocatechin gallate (GCG) also inhibited activity.

• 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)

• 한국식품저장유통학회지
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• 제8권4호
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• pp.385-392
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• 2001

다양한 침지 저장액에 의한 깐밤의 갈변억제에 따른 저장 효과를 비교하였다. 총 폴리페놀의 함량은 저장초기에 13.36 mg%로 매우 낮게 나타났으나, 무처리구는 저장 17일까지 59.12 mg%로 증가 후 다시 감소하였다. 전해산화수 처리구는 저장 8일에 61.02 mg%로 갑작스런 증가를 보인 후 감소하였고, 그 외의 처리구에서는 저장 초기에 미세한 변화를 보이다가 저장 11일에 갑작 스럽게 증가하는 경량을 나타내었다. Polyphenol oxidase 활성의 변화는 기질의 증가시기보다 조금 앞서 증가되기 시작하였으며, 무처리구가 저장 11일에 1,152 units로 가장 높은 활성을 나타내었다. 그리고 명반수 처리구가 저장 8일에 1,117 units로 다른 처리구에 비하여 높은 활성을 나타내었다. 4주간 저장하였을 때에는 유자와 레몬과즙 첨가 전해산화수 처리구가 각각 143.3 units와 180.22 units을 나타내어 타 처리구에 비하여 갈변이 억제되는 것으로 나타났다. 색도 및 관능검사를 통하여 저장기간을 예측하며 본 결과, 무처리구의 경우는 14일, 명반수, 전해산화수 및 NaCl을 첨가한 전해산화수의 경우는 21일, 유자와 레몬을 첨가한 전해산화수 처리구는 28일까지도 저장이 가능한 것으로 나타났다.

• 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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• 제52권3호
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• pp.289-295
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• 2007

본 연구는 적변 유발 세균에 의해 발생하는 적변삼과 polyphenol 및 polyphenol oxidase 활성과의 관계를 조사하였으며, 이는 다음과 같다. 1. 적변 유발 균주를 상처낸 건전 인삼 외피에 접종하여 무처리구와 비교하였을 때, 접종일수의 증가에 따라 Hue angle값이 접종 후 1일 101.2, 10일 95.9, 20일 90.1, 30일 60.9로 적색으로 변화되었다. 2. Lysobacter gummosus, Pseudomonas veronii 및 Agrobacterium tumefaciens 균주를 인삼의 상처부위에 접종하였을 때, 총페놀의 함량은 일수가 경과할수록 증가하였다. 3. Lysobacter gummosus, Pseudomonas veronii 및 Agrobacterium tumefaciens 균주를 상처낸 인삼에 접종하였을 때 페놀함량의 증가와 함께 효소의 활성이 증가하였으나 단백질당 PPO의 활성은 감소하였다.