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Lipoxygenase Activity (lipoxygenase + activity)

Distribution by Scientific Domains

Chemistry	61%
Life Sciences	30%

Selected Abstracts

LIPOXYGENASE ACTIVITY IN PRICKLY PEAR FRUIT (OPUNTIA FICUS INDICA [L.] MILL.

JOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2010
CACTACEAE)
ABSTRACT Prickly pear LOX activity was detected in the membrane fractions of the fruit extracts at various stages of ripening. LOX specific activity was very low in the fruit of wild plants at the green stage (0.49 ± 0.04) and increased with fruit ripening, more than doubling in the ripened fruit (1.22 ± 0.06). Moreover, it was not influenced by the cultivar, whereas it was considerably increased (13.3 ± 1.4) by agronomic processes to which prickly pear plants are submitted to improve the organoleptic properties of fruits. The apparent molecular mass of the enzyme was estimated to be 96 kDa. The enzyme had an optimum pH value of 5.5 and a clear specificity for linolenic acid, which was oxidized at a rate one and a half times that of linoleic acid, under the same reaction conditions. The involvement of prickly pear LOX in the flavor biosynthesis of the fruit is supposed. PRACTICAL APPLICATIONS Over the last decade in particular, prickly pear fruits have been widely used as food, not only the whole fruit but also processed to make juices, jams and liquors popular the world over. Prickly pear production has therefore risen considerably and consequently both the labor force employed and revenues generated have increased. For those engaged in this sector it is therefore a prime objective to maximise the profile and thereby profitability of the fruit. It is here that our research into lipoxygenase activity can play a part, as it is known that this enzyme is responsible for the organoleptic properties of fruits and vegetables. The results are presented below. The relationship between lipoxygenase specific activity and specific agronomic processes utilized to improve the fruit quality is also addressed. [source]

Delimiting morphologically identical varieties of soybean [Glycine max (L.) Merr.] using lipoxygenase activitity level

FEDDES REPERTORIUM, Issue 3-4 2005
M. S. Ayodele
The occurrence of beany flavour resulting from lipoxygenase activity in soybeans was sufficiently manifested in all the 22 varieties of soybean investigated. There were significant differences in the level of lipoxygenase activity among varieties. A positive correlation was observed between lipoxygenase activity and beany flavour. Lipoxygenase activity level was found reliable in delimiting the varieties. A considerable degree of overlaps and associations were observed among the varietal grouping based on lip- oxygenase activity values. Such overlaps corroborate the reported closeness of plant morphological attributes of the varieties. Lipoxygenase activity was therefore, considered a reliable chemotaxonomic tool that could be useful for taxa delimitation, where there are very similar morphological attributes that may hinder easy delimitation. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Abgrenzung von morphologisch identischen Varietäten der Soyabohne [Glycine max (L.) Merr.] mittels aktiver Lipoxygenase Das Auftreten eines bohnenähnlichen Geruchs (soybean flavour) als Ergebnis der Lipoxygenase-Aktivität wurde in allen untersuchten 22 Sojabohnen-Sorten eindeutig nachgewiesen. Im Niveau der Lipoxygenase-Aktivität treten zwischen den einzelnen Sorten manifeste Unterschiede auf. Zwischen der Lipoxygenase-Aktivität und dem bohnenartigen Geruch wurde eine positive Korrelation beobachtet. Die Höhe der Lipoxygenase-Aktivität trennt die Sorten zuverlässig. Ein beträchtlicher Grad an Überschneidungen und von Gemeinsamkeiten wurde zwischen den auf Grund der Lipoxygenase-Aktivitätswerte gebildeten Sortengruppen gefunden. Die Überschneidungen bestätigen die Nähe der morphologischen Merkmale der Sorten. Die Lipoxygenase-Aktivität wird daher als eine verlässliche taxonomische Hilfe für die Trennung der Sippen angesehen, deren große morphologische Nähe eine leichte Trennung erschwert. [source]

Retention of Folate, Carotenoids, and Other Quality Characteristics in Commercially Packaged Fresh Spinach

JOURNAL OF FOOD SCIENCE, Issue 9 2004
S. Pandrangi
ABSTRACT: The effect of storage temperature (4 °C, 10 °C, and 20 °C) on retention of folate, carotenoids, and other quality characteristics in commercially packaged fresh spinach were determined. Based on visual color and appearance, spinach was unacceptable after 8 d, 6 d, and 4 d at 4 °C, 10 °C, and 20 °C, respectively. Color differences (AE), chlorophyll degradation, fresh weight loss, and microbial populations increased at all storage temperatures and occurred more rapidly at higher temperatures. Peroxidase activity increased but was not significantly (P > 0.05) affected by storage temperature. Lipoxygenase activity was unaffected by storage time or temperature. Substantial losses of nutrients occurred at each storage temperature. Only 53% of folate in packaged spinach was retained after 8 d, 6 d, and 4 d at 4 °C, 10 °C, and 20 °C, respectively. Carotenoid losses increased with temperature with only 54%, 61%, and 44%, respectively, of initial detected levels remaining. Vitamin and quality changes were unaffected by presence or absence of packaging. [source]

LOX-Induced Lipid Peroxidation Mechanism Responsible for the Detrimental Effect of Marine Diatoms on Zooplankton Grazers

CHEMBIOCHEM, Issue 15 2007
Angelo Fontana Dr.
Abstract Some marine diatoms negatively affect the reproduction of dominant zooplankton grazers such as copepods, thus compromising the transfer of energy through the marine food chains. In this paper, the metabolic mechanism that leads to diatom-induced toxicity is investigated in three bloom-forming microalgae. We show that copepod dysfunctions can be induced by highly reactive oxygen species (hROS) and a blended mixture of diatom products, including fatty acid hydroperoxides (FAHs); these compounds display teratogenic and proapoptotic properties. The process is triggered by the early onset of lipoxygenase activities that elicit the synthesis of species-specific products, the basic structures of which were established (1,20); these compounds boost oxidative stress by massive lipid peroxidation. Our study might explain past laboratory and field results showing how diatoms damage zooplankton grazers even in the absence of polyunsaturated aldehydes, a class of molecules that has been formerly implicated in mediating the toxic activity of diatoms on copepods. [source]

Delimiting morphologically identical varieties of soybean [Glycine max (L.) Merr.] using lipoxygenase activitity level

LIPOXYGENASE ACTIVITY IN PRICKLY PEAR FRUIT (OPUNTIA FICUS INDICA [L.] MILL.

Inhibition of Oxidative and Antioxidative Enzymes by Trans-Resveratrol

JOURNAL OF FOOD SCIENCE, Issue 2 2001
X. Fan
ABSTRACT: Trans-resveratrol, a phytoalexin produced by a variety of plants, has been shown to inhibit oxidative enzymes in an animal cell system. Its effect on several oxidative and antioxidative enzymes from plants was investigated using in vitro assays. Trans-resveratrol inhibited superoxide dismutase, lipoxygenase, catalase, peroxidase, polyphenol oxidase, and 1-aminocyclopropane-1-carboxylic acid oxidase with apparent KI's of 10, 90, 100, 255, 305, and 350 ,M, respectively. Trans-resveratrol inhibited lipoxygenase activity more effectively than other lipoxygenase inhibitors, including propyl gallate, ibuprofen, ursolic acid, acetylsalicylic acid, and salicylhydroxamic acid. [source]

Environmental conditions in relation to stress in cherry tomato fruits in two experimental Mediterranean greenhouses

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2009
Miguel A Rosales
Abstract BACKGROUND: Considering the economic importance of tomato and its nutritional benefits to human health, a study was conducted on how different environmental factors (temperature, solar radiation and vapour pressure deficit (VPD)) influence hydrogen peroxide detoxification and several stress indicators in cherry tomato (Solanum lycopersicum cv. Naomi) fruits grown in two experimental Mediterranean greenhouses of parral (low-technology) type and multispan (high-technology) type. RESULTS: Three fruit samplings were made at the beginning, middle and end of the fruit production period. Values of temperature, solar radiation and VPD peaked at the third sampling in both greenhouses, being higher in the parral-type greenhouse, while there was a reduction in market production at the third sampling. Peroxidation (malondialdehyde content and lipoxygenase activity) increased significantly at the third sampling, indicating the presence of oxidative stress caused by the rise in temperature, solar radiation and VPD. The ascorbate content, the activities of superoxide dismutase, catalase and ascorbate peroxidase and other stress indicators (proline and sucrose degradation) also increased at the third sampling. CONCLUSION: This study showed that conditions of higher environmental stress occurred at the third sampling and in the parral-type greenhouse, leading to the accumulation of ascorbic acid in cherry tomato fruits and therefore to higher nutritional quality. Copyright © 2009 Society of Chemical Industry [source]

Use of a spouted bed to improve the storage stability of wheat germ followed in paper and polyethlyene packages

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2005
Füsun Yöndem-Makasc
Abstract Stabilization of wheat germ by heating in a spouted bed for 180,540 s with air at 140,200 °C was studied. The lipase activity decreased by 6,65%. Wheat germ processed at 200 °C for 360 s was ranked highest in sensory evaluation, described as having ,a golden color' and ,nutty flavor', and its lipoxygenase activity had decreased by 91.2%. This product and raw wheat germ were stored in paper, polyethylene and vacuum-packed polyethylene pouches at 5 °C, room temperature (18,26 °C) and 40 °C, and the moisture contents, water activities, free fatty acid contents and peroxide values were followed for 20 weeks. The increases were faster in paper pouches than in the polyethylene ones; vacuum packaging in polyethylene did not bring about significant improvement. The peroxide values of raw samples exceeded 10 meq O2 kg,1 oil after 3,23 days while those of the processed samples stored at room temperature or 5 °C were still less than 10 after 20 weeks. The free fatty acid content and peroxide value changes were expressed by zero order kinetics, resulting in similar activation energies for the raw and processed samples. Copyright © 2005 Society of Chemical Industry [source]

Antioxidant and DNA protecting properties of anti-fatigue herb Trichopus zeylanicus

PHYTOTHERAPY RESEARCH, Issue 8 2005
Binu Tharakan
Abstract Chronic fatigue is considered a complex symptom for which currently there is no curative treatment available. Oxidative stress plays an important role in the etiology of fatigue and antioxidant treatment might be a valuable therapeutic approach. The Kani, a tribal high altitude living population in southern India, traditionally use the seeds of Trichopus zeylanicus to combat fatigue. In this study, the antioxidant properties of Trichopus zeylanicus were established on free radicals (DPPH and ABTS), its ability to reduce iron, lipoxygenase activity and hydrogen peroxide-induced lipid peroxidation. The effects of Trichopus zeylanicus on reactive oxygen species induced plasmid DNA (pBR322) cleavage were also investigated. Trichopus zeylanicus significantly scavenged free radicals, reduced lipid peroxidation and inhibited lipoxygenase activity. Trichopus zeylanicus also exhibited iron-chelating activity and inhibited reactive oxygen species induced DNA damage. Trichopus zeylanicus contains NADH, polyphenols and sulfhydryl compounds, which have the ability to scavenge reactive oxygen species suggesting that the antioxidant activity may be an important mechanism of action of Trichopus zeylanicus to combat fatigue. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Production and detoxification of H2O2 in lettuce plants exposed to selenium

ANNALS OF APPLIED BIOLOGY, Issue 1 2009
J.J. Ríos
Abstract Selenium is considered an essential element for animals. Despite that it has not been demonstrated to be essential for higher plants, it has been attributed with a protective role against reactive oxygen species in plants subjected to stress. In this study, lettuce plants (Lactuca sativa cv. Philipus) received different application rates (5, 10, 20, 40, 60, 80 and 120 ,M) of selenite or selenate, with the aim of testing the effect of Se on the production and detoxification of H2O2 in non-stressed plants. The results indicate that the form selenate is less toxic than selenite; that is, the plants tolerated and responded positively to this element, and even increasing in growth up to a rate of 40 ,M for the form selenate. On the contrary, the application of selenite triggered a higher foliar concentration of H2O2 and a higher induction of lipid peroxidation [malondialdehyde content and lipoxygenase activity] in comparison to that observed after the selenate application. Also, the plants treated with selenate induced higher increases in enzymes that detoxify H2O2, especially ascorbate peroxidase and glutathione (GSH) peroxidase, as well as an increase in the foliar concentration of antioxidant compounds such as ascorbate and GSH. These data indicate that an application of selenate at low rates can be used to prevent the induction in plants of the antioxidant system, thereby improving stress resistance. [source]

Mung bean lipoxygenase in the production of a C6-aldehyde.

BIOTECHNOLOGY JOURNAL, Issue 11 2007
Natural green-note flavor generation via biotransformation
Abstract Mung bean was investigated as a novel source of lipoxygenase in the natural production of the green-note aroma compound hexanal. Lipoxygenase extracted from mung bean catalyzed the oxidative reaction of linoleic acid, after which the intermediate hydroperoxide compound was split via green bell pepper hydroperoxide lyase to produce hexanal. In comparison to soybean lipoxygenase, mung bean lipoxygenase was found to be a good substitute as it produced 15.4 mM (76% yield) hexanal while soybean gave 60% yield. The mung bean pH profile comprised a wide peak (optimum pH 6.5) representing lipoxygenase-2 and lipoxygenase-3 isozymes, whereas two narrower peaks representing lipoxygenase-1 and lipoxygenase-2/3 isozymes were observed for soybean (optimum pH 10). Extraction at pH 4.5 was preferred, at which specific lipoxygenase activity was also the highest. [source]

Photoactivation of an Inhibitor of the 12/15-Lipoxygenase Pathway

CHEMBIOCHEM, Issue 7 2006
Stephan Herre
Abstract Lipoxygenases are lipid-peroxidizing enzymes that have been implicated in the pathogenesis of inflammatory diseases and lipoxygenase inhibitors may be developed as anti-inflammatory drugs. Structure comparison with known lipoxygenase inhibitors has suggested that (2Z)-2-(3-benzylidene)-3-oxo-2,3-dihydrobenzo[b]thiophene-7-carboxylic acid methyl ester might inhibit the lipoxygenase pathway but we found that it exhibited only a low inhibitory potency for the pure 12/15-lipoxygenase (IC50=0.7 mM). However, photoactivation, which induces a Z -to- E isomerization of the double bond, strongly augmented the inhibitory potency and an IC50 value of 0.021 mM was determined for the pure E isomer. Similar isomer-specific differences were observed with the recombinant enzyme and its 12-lipoxygenating Ile418Ala mutant, as well as in intracellular lipoxygenase activity. Structure modeling of the enzyme/inhibitor complex suggested the molecular reasons for this isomer specificity. Since light-induced isomerization may proceed in the skin, such photoreactive compounds might be developed as potential drugs for inflammatory skin diseases. [source]