• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.777-784
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• 1993

The bleaching effect of potato lipoxygenase Isoenzymes on ${\beta}-carotene$ was studied. Two lipoxygenase Isoenzymes(LOX-1, LOX-2) from potato tuber were purified by CM-cellulose, DEAE-cellulose ion exchange chromatography. LOX-1 and LOX-2 seemed to have bleaching effect on ${\beta}-carotene$ in the presence of linoleic acid, which the decrease in the formation of conjugated dienes. LOX-2 was founded to have a greater pigment bleaching activity than that of LOX-1.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.321-329
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• 2013

Although it has been reported that lysyl oxidase (LOX) is involved in odontoblastic differentiation, the role of LOX on odontoblastic differentiation by hydrogen peroxide ($H_2O_2$) have not been clarified. In the present study, we investigated whether $H_2O_2$, reactive oxygen species (ROS), is modulated the messenger RNA (mRNA) expression and activity of LOX during odontoblastic differentiation of human dental pulp (HDP) cells. The mRNA expression was quantified by reverse transcriptase polymerase chain reaction (RT-PCR) analysis, and LOX enzyme activity was measured by high sensitive fluorescent assay. Expression of the odontoblastic differentiation marker genes were assessed in the presence and absence of specific small interfering RNAs (siRNAs) of the LOX and LOXL. The $H_2O_2$-induced mRNA expression of LOX family was significant reduction of LOX, LOXL, and LOXL3 mRNA levels in HDP cells. LOX enzyme activity was increased at $H_2O_2$ 0.3 mM for 24 hours. The mRNA expression of alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) was inhibited by LOX- and LOXL-specific siRNAs whereas the mRNA expression of dentin matrix protein1 (DMP1), and dentin sialophosphoprotein (DSPP) was inhibited by LOX-specific siRNA. In LOX enzyme activity, siRNA-induced knockdown of both LOX and LOXL inhibited the total amine oxidase activity in HDP cells, as in the case of mRNA expression. In conclusion, the essential role of $H_2O_2$ on odontoblastic differentiation suggests that its regulation by LOX may have pharmacologic importance in HDP cells.

• Applied Biological Chemistry
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• v.38 no.5
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• pp.414-421
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• 1995

In order to establish informations important to the measurement of lipoxygenase (LOX) activity, providing conditions most favorable for its action and determining factors that inhibit activity, the influence of extraction buffer, substrate, pH, storage, temperature, NaCl, $CaCl_2$, other cations and antioxidants on LOX activity, and localization of LOX in cucumber tissues were carried out. The most favored substrate for LOX was linolenic acid followed by linoleic and arachidonic acids. LOX activity in both peel and mesocarp tissue extracts was maximum at pH 5.5 and relatively stable at $40^{\circ}C\;and\;50^{\circ}C$ temperature. The condition of 0.2 M NaCl with pH 5.0 was observed to provide optimum LOX stability. The enzyme activity was reduced by addition of cations, $Mn^{2+},\;Cu^{2+}\;or\; Al^{3+}$, except $Ca^{2+}$ which stimulated activity of LOX. Butylated hydroxy anisole (BHA) and propyl gallate decreased LOX activity with increasing concentration. Cucumber peel had higher activity than other tissues, locule or mesocarp, of cucumber.

• Nutritional Sciences
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• v.9 no.3
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• pp.212-226
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• 2006

The involvement of arachidonic acid (AA) metabolizing enzyme, lipoxygenase (LOX), in the development of particular tumors in humans has gradually been acknowledged and LOX has emerged as a novel target to prevent or treat human cancers. In the mouse skin carcinogenesis model, which provides an excellent model to study multistage nature of human cancer development, many studies have shown that some of the LOXs are constitutively upregulated in their expression. Moreover, application of LOX inhibitors effectively reduced tumor burdens, which implicates the involvement of LOX in mouse skin tumor development as well. 8S-LOX is a recently cloned LOX, which is specifically expressed in mouse skin after 12-O-tetradecanoyl-phorbol-13-acetate (TPA) treatment but not in normal skin. Unlike other members of the LOX 'family' expressed in mouse skin, this TPA-induced expression of 8S-LOX is prominent only in the skin of the TPA tumor promotion-sensitive strains of mice (SENCAR, CD-1, and NMRI) but not in the promotion-resistant C57BL/6J mice. This is a very unique phenomenon among strains of mice. Constitutive upregulation of 8S-LOX was also found in early stage papillomas and the expression was gradually reduced as the tumors became malignant. Based on these observations, it has been thought that 8S-LOX is involved in TPA-induced tumor promotion as well as in tumor conversion from papillomas to carcinomas. In accordance with this hypothesis, several studies have suggested possible roles of 8S-hydroxyeicosatetraenoic acid (HETE), an AA metabolite of 8S-LOX, in mouse skin tumor development. A clastogenic activity of 8S-HETE was demonstrated in primary keratinocytes and a close correlation between the levels of etheno-DNA adducts and 8S-HETE during skin carcinogenesis was also reported. On the other hand, it has been reported that 8S-LOX protein expression is restricted to a differentiated keratinocyte compartment Moreover, reported findings on the ability of 8S-HETE to cause keratinocyte differentiation appear to be contrary to the procarcinogenic features of the 8S-LOX expression, presenting a question as to the role of 8S-LOX during mouse skin carcinogenesis. In this review, molecular and biological features of 8S-LOX as well as current views on the functional role of 8S-LOX/8S-HETE during mouse skin carcinogenesis are presented.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.296-303
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• 2013

Lysyl oxidase (LOX), extracellular matrix enzyme, is catalyzing lysine-derived crosslinks in collagen and elastin. Recently, several LOX-like proteins (LOXL, LOXL2, LOXL3 and LOXL4) have been identified in human but their specific functions are still largely unknown. The purpose of this study was to evaluate the function of the LOX family genes during odontoblastic differentiation of human dental pulp (HDP) cells induced with odontogenic supplement (OS). The messenger RNA (mRNA) expression of LOX family genes and differentiation markers was assessed by reverse transcriptase polymerase chain reaction analysis (RT-PCR). The formation of mineralization nodules was evaluated by alrizarin red S staining. Amine oxidase activity of HDP cells was measured by peroxidase-coupled fluormetric assay. The expressions of differentiation markers, such as alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), dentin matrix protein1 (DMP1), dentin sialophosphoprotein (DSPP) in HDP cells were increased after treatment with OS media. The LOX and LOXL mRNA expression were gradually increased in OS media, whereas LOX enzyme activities were markedly detected on day 7. The mRNA expression and LOX enzyme activity of collagen type I was very similar to the pattern of LOX gene. In this study, the expression of LOX and its isoforms, and activity of LOX were highly regulated during odontoblastic differentiation. Thus, these results suggest that LOX plays a key role in odontoblastic differentiation of HDP cells.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.353-357
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• 2005

LOx post damage occurs from the development process of the full-scale gas generator which is necessary to 30 tonf class engine development was described. The cause and analysis for damage was described. The combustion test result of 4 injector, the full-scale gas generator and redesigned injector was described. Combustion instability, purge, the low momentum of LOx spray, small recess number, the low flow of LOx, and the high spray angle is main reason the possibility of knowing. The redesign for the injector in the direction of increase of recess number, increase of LOx and fuel spray angle, decrease of gap interval between the LOx post outer wall and fuel screen and increase of LOx post wall thick became accomplished.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.294-303
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• 2023

Lipoxygenase gives soybeans their grassy flavor, which can disrupt food processing efficiency. This study aimed to identify soybean genotypes with lipoxygenase deficiency among 1,001 soybean accessions and to develop kompetitive allele specific PCR (KASP) markers that can detect lipoxygenase mutations. Three lipoxygenase isozymes (Lox1, Lox2, and Lox3) were analyzed using a colorimetric assay based on a substrate-enzyme reaction. Among the 1,001 accessions examined, two (IT160160 and IT276392) exhibited a deficiency solely in Lox1, and one (IT269984) lacked both Lox1 and Lox2. IT160160 had a 74-bp deletion in exon 8 of Lox1 (Glyma13g347600), whereas IT276392 displayed a missense mutation involving the change of C to A at position 2,880 of Lox1. Moreover, we successfully developed four KASP markers that specifically target Lox1, Lox2, and Lox3 mutations. To validate the Lox1 KASP markers, we used two F_2:3 populations generated through a cross between Daepung 2 (lipoxygenase wild type, maternal parent), IT160160, and IT276392 (null Lox1, paternal parent). The results revealed that the Daepung 2 × IT160160 group followed the expected 3:1 ratio according to Mendel's law, whereas the Daepung 2 × IT276392 group did not. Furthermore, a comparison between the colorimetric and KASP marker analyses results revealed a high agreement rate of 96%. KASP markers offer a distinct advantage by allowing the distinction of heterozygous types independent of other variables. As a result, we present an opportunity to expedite the lipoxygenase-deficient cultivar development.

• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.41-46
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• 2006

A study was conducted to investigate the problem caused by the mechanical particles in LOX system during operating and testing propulsion system, especially concentrated on effects of contaminants accumulation and transfer in LOX system. Several methods for system operation decreasing accidents caused by oxidizer Beakage and contaminants accumulation was investigated. These methods can be applied to LOX system and other propellants system in liquid propellants propulsion system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.954-958
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• 1994

The bleaching effect of chlorophyll a by two lipoxygenase isoenzymes (LOX-1, LOX-2) isolated from potato tuber(variety DEinma ) was studied. In the presence of LOX-1 or LOX0-2 with linoleic acid chlorophyll a bleaching occurred during two isoenzymes-mediated oxidation of linoleic acid. Chlorophyll a bleaching porceeded with decreasing in the formation of conjugated dienes form linoleic acidyb LOX-1 and LOX-2 . In the presence of chlorophyll a, LOX-2 showed a markable decrease inproduction of conjugated dienes from linoleic acid and a higher chlorophyll a bleaching activity. compared with LOX-1. These results suggest chlorophyll-bleaching reaction required intermediates formed during the peroxidation of linoleic acid by lipoxygenase isoenzymes, thus preventing formation of conjugated dienes.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.437-441
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• 2008

A non-toxic Post Boost Stage(PBS) with LOX/Ethanol engine was successfully demonstrated at the Tomioka Facility of IHI Aerospace. IHI Aerospace has researched and developed the nontoxic propulsion systems and the LOX/Ethanol is one of the most attractive non-toxic bipropellant candidates. ${\rho}ISP$ of LOX/Ethanol is higher than ${\rho}ISP$ of the other non-toxic bipropellants as LOX/HC or $LOX/LH_2$. The authors studied the combustion characteristics of LOX/Ethanol propellant with the engine designed for LOX/LNG propellant. Also the injector with a built-in igniter was designed and examined its feasibility, ignition and combustion characteristics. We have demonstrated Post Boost Stage with future LOX/Ethanol engines. This propulsion system is targeted for expandable vehicle upper stage to accelerate delta-V to reach the required orbit. PBS Demonstration Model is designed as a test stand to evaluate feed system for integrated propulsion system and also to demonstrate Integrated Vehicle Health Management(IVHM) technique using local valve control and also valve behavior-monitoring capability.