• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.211-215
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• 1994

Lipoxygenase is involved in the formation of certain undesirable flavors of soybean products. Three isozymes(L-1, L-2 and L-3) of lipoxygenase have been identified in soybean seeds, and the three types of mutants lacking L-1, L-2 and L-3, respectively, were detected in the 1980's. In this paper, lipoxygenase activity was measured to investigate the response of lipoxygenase in organs and tissues during soybean development. There was no tendency according to genotypes between lipoxygenase lacking mutants and normal soybeans in lipoxygenase activity of leaf at $V_3$ and $V_5$ stage. Likewise, pod wall lipoxygenase was no difference among genotypes tested at R$_{6}$ stage. Seed coat lipoxygenase activity was similar among the lipoxygenase lacking mutants, while normal soybean was lower as compared with that of the lipoxygenase lacking mutants. Embryo and cotyledon lipoxygenase activity in the lipoxygenase lacking mutants was much lower than that of normal soybean, also there was large difference among lipoxygenase lacking mutants. Thus, the lipoxygenase null mutant showed very weak value although the lacking L-3 mutant had a large effect on developing embryo lipoxygenase activity. It was suggested that soybean lipoxygenase isozymes expressed in embryo may be different from those expressed in the pod wall and leaf tissues.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.3
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• pp.209-214
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• 2006

Three lipoxygenase isozymes in soybean seeds are thought to be a major contributor to lipid peroxidation and generation of free radicals which may result in seed deterioration. This study was conducted to get the basic information for changing lipoxygenase activity during seed germination in lipoxygenase-lacking soybeans. Fresh weight of soybean seedling of Jinpumkong 2 and Taekwangkong increased more rapidly than that of Jinpumkong. Hypocotyls of Jinpumkong and Jinpumkong 2 were longer and thicker than that of Taekwangkong. Type I lipoxygenase activity (pH 9.0) in cotyledon of Jinpumkong lacking lipoxygenase-2, 3 showed higher than that of Taekwangkong, and Type I lipoxygenase activity of two cultivars decreased continually. On the other hand, Type II lipoxygenase activity of Taekwangkong began to increase continually two days after germination, reached to the maximum between 4 days and 5 days, and began to decrease continually five days after germination. Type I and II lipoxygenase activity in hypocotyls was not detected in all soybean cultivars.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.441-445
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• 1987

The subcellular distribution of lipoxygenase in germinating soybean seeds (Glycine max[L.] AmSoy) was investigated by using differential centrifugation and sucrose density gradient fractionation. Most of lipoxygenase -1 and -2/3 activities was present in the supernatant fraction after differential centrifugation of homogenates prepared from three-day-old seedlings; only 1.5% of lipoxygenase activity remained in particulate fractions. The results of a sucrose density gradient fractionation (three-day-old) showed that the lipoxygenase activity coincided with acid phosphatase at the densities of 1.19, 1.23, $1.25g/cm^3$, even though most of lipoxygenase and acid phosphatase activities appeared in supernatant fractions. There was no indication that mitochondria contained any lipoxygenase activity, and it does not appear that glyoxysomes and ER contained any lipoxygenase activity either.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.314-319
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• 1997

The objectives of this study were to examine the effect of storage time, temperature, pH, and NaCl concentration on hydroperoxide lyase and lipoxygenase activities, and to establish important informations to the production of typical cucumber flavor. Conditions affecting lipoxygenase and hydroperoxide lyase would be important for cucumber flavor production. Maximum activity was observed at pH 5.0 for hydroperoxide lyase and pH 5.5 for lipoxygenase. Both enzymes were relatively stable at $40\;to\;50^{\circ}C$ for 6days storage time. Maximum activity of both enzymes was observed with 0.2 M NaCl at pH 5.0. Activities were stimulated with concentrations of NaCl from 0.05 to 0.2 M. Hydroperoxide lyase and lipoxygenase activities were decreased at concentration of NaCl greater than 0.2 M.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.112-117
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• 2005

This study was conducted to see the feasibility of breeding for sprout soybean cultivar with minimum benny flavor using lipoxygenase-less lines. Lipoxygenase-less cultivar Jinpumkong2 was crossed by lipoxygenase containing Gwangankong, Sebaeknamulkong, and Pureunkong as paternal parent and 24 lipoxygenase-less lines derived from those 3 combinations were selected and those lines were evaluated with their parental cultivars. Germination rate showed no difference between lipoxygenase-less lines and their parental cultivars, however, rates of normal sprout of those and Jinpumkong2 were 63 and $56\%$, and were lower than that of paternal parents. Hypocotyl length of those was same as Jinpumkong2, however, shorter than paternal parents. Texture characteristics including hardness, cutting force and mastication of 96 hour-cultured sprout of lipoxygenase-less lines showed higher value than that of their parental cultivars. Lipoxtgenase isozyme was not detected in the sprout cotyledon of lipoxygenase-less lines, however it was observed in the sprout hypocotyl of all the used genotypes. Though lipoxygenase activity in the seed of lipoxygenase-less lines was lower than that of Jinpumkong2(0.477, ${Delta}A$ 234 nm min-1 mg meal-1),2 lines revealed more than 0.5 value. Lipoxygenase-activity of 2 day-cultured sprout(both cotyledon and hypocotyl) was the highest, decreased in 3 days after culture and re-increased thereafter. Several lipoxygenase-less lines with lower lipoxygenase activity of sprout than Jinpumkong2 were selected and this suggested the possibility of breeding lines for soy-sprout with low benny flavor.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.739-747
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• 1997

This study was performed to clarify various conditions on the test of lipoxygenase-l and to establish the application of new test method for varietal improvement of soybeans in order to decrease beany flavors. Potassium borate and Tris were used as buffer and O.1M potassium borate solution showed the best result for the lipoxygenase-l test. In the range of pH 8.5~9.0 of the buffer, 2mM linoleic acid as substrate was effective. For color development, 100$\mu$l of two solutions(KI and starch) were added to the half soybean seed, successively. The substrate solution included linoleic acid was stored safely for 10 days at 4$^{\circ}C$ in refrigerator and for 4 days at room temperature. The best result was as follows; the 1ml of substrate solution[0.1M potassium borate(pH 9.0), 0.1％ Tween-20, 2mM linoleic acid] was added to the chipped half soybean seed in l.5ml plastic tube, waited for 15 minutes, and 100$\mu$l of color development solutions(5％ saturated KI in 15％ acetic acid, 1％ starch) were added to the tube, successively. After 4 hours, the purple color was observed in the upper phase of the plastic tube in the presence of lipoxygenase-1 and milky color in absence of lipoxygenase-1. The purple color was stable from 4 to 24 hours. There was no interfering effect by lipoxygenase-2 and -3. The plastic tube should be placed in the tube stand without shaking during the lipoxygenase-l test.

• BMB Reports
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• v.33 no.2
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• pp.172-178
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• 2000

The lipoxygenase was purified 35 fold to homogeneity from the Korean red potato by an ammonium sulfate precipitation and DEAE-cellulose column chromatography. The simple purification method is useful for the preparation of pure lipoxygenase. The molecular weight of the enzyme was estimated to be 38,000 by SDS-polyacrylamide gel electrophoreses and Sepharose 6B column chromatography. The purified enzyme with 2 M $(NH_4)_2SO_4$ in a potassium phosphate buffer, pH 7.0, was very stable for 5 months at $-20^{\circ}C$. Because the purified lipoxygenase is very stable, it could be useful for the screening of a lipoxygenase inhibitor. The optimal pH and temperature for lipoxygenase purified from the red potato were found to be pH 9.0. and $30^{\circ}C$, respectively. The Km and Vmax values for linoleic acid of the lipoxygenase purified from the red potato were $48\;{\mu}M$ and $0.03\;{\mu}M$ per minute per milligram of protein, respectively. The enzyme was insensitive to the metal chelating agents tested (2 mM KCN, 1 and 10mM EDTA, and 1 mM $NaN_3$), but was inhibited by several divalent cations, such as $Cu^{++}$, $Co^{++}$ and $Ni^{++}$. The essential amino acids that were involved in the catalytic mechanism of the 5-lipoxygenase from the Korean red potato were determined by chemical modification studies. The catalytic activity of lipoxygenase from the red potato was seriously reduced after treatment with a diethylpyrocarbonate (DEPC) modifying histidine residue and Woodward's reagent (WRK) modifying aspartic/glutamic acid. The inactivation reaction of DEPC (WRK) processed in the form of pseudo-first-order kinetics. The double-logarithmic plot of the observed pseudo-first-order rate constant against the modifier concentration yielded a reaction order 2, indicating that two histidine residues (carboxylic acids) were essential for the lipoxygenase activity from the red potato. The linoleic acid protected the enzyme against inactivation by DEPC(WRK), revealing that histidine and carboxylic amino acids residues were present at the substrate binding site of the enzyme molecules.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.576-580
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• 1997

Lipoxygenase activity in Chinese cabbage was measured at various concentrations of brines. Lipoxygenase activity on linoleic acid substrate was determined by changing the rate of dissolved oxygen consumption. The inactivation of lipoxygenase by salting was increased when concentration of sodium chloride and soaking time were increased. About 60% of enzyme activity was reduced after submerging in 13% brine solution for 5 hr. The addition of calcium chloride (0.7%) reduced about $10{\sim}15%$ of lipoxygenase activity rather than without. Residual activity of lipoxygenase in Chinese cabbage submerged in 13% brine was 20% and about 60% of lipoxygenase was also inhibited by addition of garlic extract.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.5
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• pp.313-320
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• 2012

In this study, we focused to identify whether eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone), an extract from Artemisia argyi folium, prevents $H_2O_2$-induced injury of cultured feline esophageal epithelial cells. Cell viability was measured by the conventional MTT reduction assay. Western blot analysis was performed to investigate the expression of 5-lipoxygenase by $H_2O_2$ treatment in the absence and presence of inhibitors. When cells were exposed to 600 ${\mu}M$ $H_2O_2$ for 24 hours, cell viability was decreased to 40%. However, when cells were pretreated with 25~150 ${\mu}M$ eupatilin for 12 hours, viability was significantly restored in a concentration-dependent manner. $H_2O_2$-treated cells were shown to express 5-lipoxygenase, whereas the cells pretreated with eupatilin exhibited reduction in the expression of 5-lipoxygenase. The $H_2O_2$-induced increase of 5-lipoxygenase expression was prevented by SB202190, SP600125, or NAC. We further demonstrated that the level of leukotriene $B_4$ ($LTB_4$) was also reduced by eupatilin, SB202190, SP600125, NAC, or nordihydroguaiaretic acid (a lipoxygenase inhibitor) pretreatment. $H_2O_2$ induced the activation of p38MAPK and JNK, this activation was inhibited by eupatilin. These results indicate that eupatilin may reduce $H_2O_2$-induced cytotoxicity, and 5-lipoxygenase expression and $LTB_4$ production by controlling the p38 MAPK and JNK signaling pathways through antioxidative action in feline esophageal epithelial cells.

• Archives of Pharmacal Research
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• v.22 no.1
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• pp.18-24
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• 1999

Various flavonoid derivatives were previously reported to possess the inhibitory activity on cyclooxygenase/lipoxygenase. And these properties of flavonoids might contribute to their anti-inflammatory activity in vivo. In this study, several polyhydroxylated/methoxylated flavonoid derivatives such as oroxylin A. wogonin, skullcapflavone II, tectorigenin and iristectorigenin A were isolated from the medicinal plants. these compounds were evaluated fro their inhibitory effects on cyclooxygenase/lipoxygenase from the homogenate of human platelets in vitro. It was found that isoflavones including daidzein and tectorigenin possessed the inhibitory activity on cycloooxygenase, although the potency of inhibition was far less than that of indomethacin. In addition, oroxylin A, baicalein and wogonin inhibited 12-lipoxygenase activity without affecting cyclooxygenase, which suggested that 5,6,7- or 5,7,8-trisubstitutions of A-ring of flavone gave favorable results. The IC50 values of oroxylin A and NDGA against 12-lipoxygenase were found to be 100 and 1.5 uM, respectively.