• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1333-1338
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• 1998

Several enzymes of kimchi ingredients were assayed to improve the product quality using these quality related enzyme information. Among various hydrolases, amylase and protease were selected with respect to lactic acid fermentation. Peroxidase and ascorbic acid oxidase were studied for off flavor production and ascorbic acid destruction. The amount of protein in kimchi ingredients, specific and total enzyme activity of sample were compared. Regarding total enzyme activity of sample, ${\alpha}-amylase$ activity of salted and fermented anchovy, dried red pepper and salted and fermented shrimp were higher than other ingredients. Activity of salted and fermented anchovy was 2,790.0 units/g sample. Salted and fermented anchovy, oyster and Chinese radish showed the highest ${\beta}-amylase$ activity (4.4, 2.1, 1.0 units/g sample, respectively). Salted and fermented anchovy showed the highest protease activity of 13.4 PU/g sample, followed by salted and fermented shrimp and dried red pepper. For peroxidase, Chinese radish, cucumber, green onion showed the highest activity of 7.2, 6.8 and 5.6 units/g sample, respectively. In case of ascorbic acid oxidase, salted and fermented anchovy showed the strongest enzyme activity (331.4 units/g sample), followed by dried red pepper and salted and fermented shrimp.

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.41-41
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• 2001

Ascorbate peroxidase catalyze the oxidation of ascorbic acid through the reaction with hydrogen peroxide. Ascorbic acid are utilized as a substrate in oxidative stress. In Candida albieans, ascorbic acid is used as antioxidants, so called D-erythroascorbic acid (EASe). Oxidative stress change concentrations of EASC resulting in interaction with alternative oxidase (AOX).(omitted)

• Applied Biological Chemistry
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• v.48 no.1
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• pp.53-59
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• 2005

The effect of various stressors such as reductant ascorbic acid, signalling molecules (salicylic acid and methyl jasmonic acid), heavy metals $(NiCl_2,\;and\;MnSO_4)$ and NaCl on the glutathione peroxidase (GPX) activities and isoenzyme expression patterns were investigated in rice seedling roots. Total GPX activity increased according to the increase of ascorbic acid concentration. Prominent enhancement of GPX1 isozyme due to ascorbic acid contributed to the increase of total GPX activity. GPX showed different reactivity toward salicylic acid and methyl jasmonic acid. GPX activity increased at 0.1 mM salicylic acid, and then decreased thereafter. However, GPX increased gradually in a methyl jasmonic acid concentration-dependent manner, and 3 fold increase of GPX activity was found at 1 mM methyl jasmonic acid. Moreover, GPX1 isozyme increased according to the increase of salicylic acid, while GPX1 isozyme decreased according to the increase of methyl jasmonic acid. When metal ions were treated, GPX activity increased considerably according to the increase of $NiCl_2$ concentration, however, GPX activity increased about 2 fold at 0.5 mM $CuSO_4$ and then decreased. Enhancement of GPX1 isozyme contributed to the increase of total GPX activities in $NiCl_2-treated$ and $MnSO_4-treated$ rice seedlings. Total GPX activity increased 1.7 fold in response to 300 mM NaCl. Especially GPX2 isozyme showed gradual increase according to the increase of NaCl concentration.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.14-18
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• 1997

The objective of this research was to increase phytoprotective effects by combined treatment of uniconazole and free radical scavengers such as ascorbic acid or sodium benzoate on $SO_2$ injury in P. occidentalis. The plant injury, chlorophyll content and enzyme activity of superoxide dismutase(SOD) and peroxidase(POD) affected by combined treatment were also investigated. The phytoprotective role of uniconazole was nullified by spray of Diethyldithiocarbamate(DDTC) resulting in the decrease of SOD and POD activities. Free radical scavengers, sodium benzoate and ascorbic acid, did not affect SOD and POD activity, but significantly inhibited the development of visible injury, degradation of chlorophyll, and SOD and POD activity in leaves exposed to $SO_2$. The spray of ascorbic acid decreased plant susceptibility to $SO_2$ induced by DDTC application. These results indicate that uniconazole application increase SOD activity that play a role of antioxidant in plant body, but sodium benzoate and ascorbic acid do not affect enzyme activities of SOD or POD.

• Applied Biological Chemistry
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• v.30 no.3
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• pp.285-290
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• 1987

As a basic research for inhibition of enzymatic browning of apples during dehydration or processing, peroxidase was extracted from Fuji apples to investigate heat inactivation, and chemical inhibition. Peroxidase showed the highest activity at $35^{\circ}C$ and pH 5.5 using substrates of p-phenylenediamine and $H_2O_2$. The thermal inactivation followed biphasic kinetics to have activation energy (Ea) of 48.2kcal/mol and z value of $11.2^{\circ}C$ for the heat labile fraction and Ea of 36.3kcal/mol and z value of $14.9^{\circ}C$ for the heat resistant fraction. Browning by peroxidase was completely inhibited at the concentrations of 10mM for sodium diethyldithiocarbamate and potassium metabisulfite and 1mM for L-cysteine and ascorbic acid.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.565-570
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• 1993

Peroxidase from Jerusalem artichoke tubers, which might be related to browning reaction, was purified by ammonium sulfate precipitation, DEAE-cellulose and Sephacryl S-200 chromatography. The optimum pH of the purified peroxidase was 5.0 and relatively stable at pH $5.0{\sim}6.0$ using substrate of p-phenylenediamine and $H_2O_2$. D-values for thermal inactivation at 60, 70 and $80^{\circ}C$ were 86, 45 and 33 sec, respectively. Activation energy was 4,111 J/mole. The enzyme showed the most sensitive specificity of substrate for p-phenylenediamine. The compounds such as 1mM potassium cyanide, 10mM sodium diethyldithiocarbamate, L-ascorbic acid, sodium hydrosulfite and L-cysteine inhibited completely while 1mM of $Ca^{2+}\;and\;Cu^{2+}$ activated the purified peroxidase.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.84-90
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• 1992

Peroxidase in the fruit of Malus sieboldii (Regel) Rehder was partially purified by DEAE-cellulose column chromatography and Ultro-AcA 54 gel filtration. The optimum pH of peroxidase was 4.5 and optimum temperature was $80^{\circ}C$. The enzyme was stable at pH 5.0 and below $30^{\circ}C$, and inactivated by heat treatment at $80^{\circ}C$ for 15min. In the presence of 30mM $H_{2}O_2$ Km value on o-phenylenediamine as substrate was 1.65mM, and in the presence of 10mM o-phenylenediamine Km value on $H_{2}O_2$ was 7.97mM. L-Ascorbic acid and sodium L-ascorbate greatly inhibited the enzyme activity and among several metal ions $Mn^{2+}$ only increased the activity at 5mM.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.506-514
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• 1987

Peroxidase was purified to a homogeneous state from Castanea Semen by ammonium sulfate precipitation, DEAE-cellulose column chromatography, gel filtration on sephadex G-100 and HPLC, and the purification fold was 65.3. The molecular weight of the enzyme was estimated to be about 35,000 by HPLC. In properties of the enzyme which was purified up to sephadex G-100 column chromatography, the optimum pH and temperature were 5.0 and $50^{\circ}C$, respectively. By heating the enzyme at $80^{\circ}C$ for 1.73 min., the enzyme activity was decreased to 10%. The enzyme was active toward aromatic amines such as o-phenylenediamine and p-phenylendiamine. Kinetic studies indicated a Km of 2.6mM for o-phenylenediamine at an optimal hydrogen-peroxide concentration and a Km of 10mM for hydrogenperoxide at an optimal o-phenylenediamine concentration. Among the reagents tested, L-ascorbic acid and sodium L-ascorbate inhibited significantly the enzyme, while $Ca^{++}$ and $Ba^{++}$ activated the enzyme at the concentration of 1mM and 5mM.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1143-1147
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• 1998

Enzymatic characterization of peroxidase(E.C. 1.11.1.7) from soybean sprouts was investigated. The optimum pH of the purified peroxidase was 7.0 and relatively stable at pH 6.0~7.0. And the optimum temperature was 50oC. The enzyme was most active with guaiacol as a substrate, followed by (＋)catechin, pyrogallol and p phenylenediamine. The Km values for guaiacol and H2O2 were 4.2mM and 2.5mM, respectively. L Ascorbic acid and 2 mercaptoethanol greatly inhibited the enzyme activity, while Cu2+, Co2+ and Ni2+ activated the enzyme.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.378-382
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• 1999

The sanitizing effect of irradiation on the fresh vegetable extract juices was investigated. Total bacteria, coliform bacteria and total ascorbic acid were determined during the storage periods at 4oC. Chlorophyll, carotenoid, tannin, electron donating ability and peroxidase activity were determined immediately after irradiation. Results showed that the viable cells were detected below the level of 105 CFU/ml during 12 days with doses of 3 and 5 kGy. Total ascorbic acid and tannin contents increased immediately after irradiation. However, irradiation didn't affect chlorophyll and car otenoid contents, electron donating ability, and peroxidase activity. It was considered that irradiation was effective in sanitizing fresh vegetable extract juices.