• 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 Life Science
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• v.10 no.3
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• pp.254-261
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• 2000

In order to observe the bioactivity of ovariectomized rats, ovariectomized group (Ovx), nonovariectomized group (Sham), ovariectomized Vitamin C-treat group (Ovx+Vit C), ovariectomized Vitamin E-treat group (Ovx+Vit E) and ovariectomized Vitamin C+Vitamin E-treat group(Ovx+Vit C+E) were made. Lipidperoxides of liver and kidney, serum total cholesterol and HDL-cholesterol were investigate as follows. Lipidperoxides of liver and kidney in Ovx group were 1.78 times and 1.61 times increased compared to Sham group respectively. But, they were significantly decreased in Ovx+Vit C group, Ovx+Vit E group, Ovx+Vit C+E group compared to Ovx group. Serum total cholesterol in Ovx group was increased 2.57 times compared to Sham group. Injections of each substance such as ascorbate, tocopherol, mixture (C+E) make data of Cholesterol become low. When especially Vit C is injected, the data of cholesterol lowed by about 94%. Serum HDL-cholesterol in Ovx group decreased 36.7% compared to Sham group. And as the result of the measurement of SOD, Catalase, and GPx which are antioxidant enzyme, SOD and Catalase activities in Ovx group much higher than in Sham group. Based on the results, it is supposed that more produced free radicals increased antioxidant enzyme. And it is also thought that vitamin can inhibit aging by reducing antioxidant enzyme.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.192-199
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• 2000

Lactic acid bacteria (LAB) fermented food was prepared from milk or egg white powder (EWP) and added with five kinds of freeze drying protectant (FDP). Effects of FDP on growth and acid production of LAB were investigated. Effects of FDP on organoleptic properties of LAB fermented food were also studied. (1) Some of FDPs showed protective effect against damage to Lactobacillus acidophilus in LAB fermented food during freeze drying, while FDP did not show any protective effect against damage to L. acidophilus during freezing. This protective effect differed with substrate and concentration of FDP (2) Optimum concentration of Tween 80 and ascorbate added to milk sample was 0.2 % (W/V) and 1 %(W/V), respectively. Optimum concentration of raffinose and ascorbate added to EWP sample was 3 %(W/V) and 1 %(W/V), respectively (3) Among FDPs added to L. casei fermented food, raffinose and ascorbate added to EWP sample showed FDP effect. Among FDPs added to L. delbrueckii fermented food, raffinose added to EWP sample showed FDP effect. (4) Samples added with MSG showed MSG taste. Milk sample added with ascorbate showed slightly more acid taste than reference sample, while taste of EWP sample added with ascobate did not differ with reference sample. Tween 80 added to milk sample or EWP sample improved texture of LAB fermented food.

• Journal of Life Science
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• v.25 no.10
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• pp.1091-1097
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• 2015

We have isolated and characterized an ascorbate peroxidase (APx) gene, OsAPx1 from rice. Northern and Western blot analyses indicated that at young seedling stage, OsAPx1 mRNA was expressed highly in root, shoot apical meristem (SAM) and leaf sheath than leaf. In mature plant, OsAPx1 gene expressed highly in root, stem and flower but weakly in leaf. OsAPx1 gene and protein expression level was induced in leaves inoculated with Magnaporthe oryzae (M. oryzae) and Xanthomonas oryzae pv. oryzae (Xoo). Phytohormones treatment showed that OsAPx1 was up-regulated by jasmonic acid (JA), but was down regulated by ABA and SA co-treatments with JA, resulting that they have antagonistic effect on pathogen responsive OsAPx1 expression. Phylogenetic analysis illustrated that Arabidopsis AtAPx1 has a close relationship with OsAPx1. In AtAPx1 knock out lines, the accumulation of O₂^- and H₂O₂ are all highly detected than wild type, revealing that the high concentration of exogenous H₂O₂ cause the intercellular superoxide anion and hydrogen peroxide accumulation in AtAPx1 knockout plant. These results suggested that OsAPx1 gene may be associated with the pathogen defense cascades as the mediator for balancing redox state by acting ROS scavenger and is associated with response to the pathogen defense via Jasmonic acid signaling pathway.