Tomatoes, lipoxygenase

Hazai, E, Z Bikadi, F Zsila, and SF. Lockwood. 2006. Molecular modeling of the non-covalent binding of the dietary tomato carotenoids lycopene and lycophill, and selected oxidative metabolites with 5-lipoxygenase. Bio Med Chem 14 6859-6867. 

Kausch KD, Handa AK. Molecular cloning of a ripening-specific lipoxygenase and its expression during wild-type and mutant tomato fruit development. Plant Physiol 1997 113 1041-1050. 

The tomato plant contains a number of enzymes that we have already discussed and that may be important mediators of resistance to insects (e.g., polyphenol oxidases, peroxidases, lipoxygenases, ureases, chitinases, phenylalanine and tyrosine ammonia lyases, en-dopolygalacturonases). We discuss here the potential interaction of these enzymes. 

A mixture of 9S-HPODE and 13S-HPODE is obtained when soybean lipoxygenase reacts with linoleic acid at pH 6,4 [156]. Lipoxygenase of tomatoes [157] produces mainly 9S-10E,12Z-octadecadienoic acid (9S-HPODE, Scheme 4) from linoleic acid and 9S,10E,12Z,15Z-octadecatrienoic acid (9S-HPOTE, Scheme 5) from linolenic acid. 

Lipoxygenase Bean, potato, tomato, maize, strawberry, canola, fish, meat Oxidation of polyunsaturated fatty acids to hydroperoxides and further into aldehydes, acids, ketones, etc. 

Galliard, T. and Matthew, J.A., Lipoxygenase-mediated cleavage of fatty acids to carbonyl fragments in tomato fruits, Phytochemistry, 16, 339, 1977. 

Riley, J.C.M., Willemot, C., and Thompson, J.E., Lipoxygenase and hydroperoxide lyase activities in ripening tomato fruit, Postharvest Biol. Tech., 7, 97, 1996. 

Enzymes other than peroxidase and catalase have been used less frequently to monitor adequacy of heat treatment. Some enzymes that have been used include polyphenol oxidase for off-color development in fruits, polygalacturonase for loss of consistency in tomatoes, potatoes and eggplants and lipoxygenase and lipase for... 

The enzymic formation of Cs- and Cg-components in vegetables is determined by the cleaving-system E2. Tomatoes possess a lipoxygenase-system which forms 9-LOOH and 13-LOOH in a ratio of 95 5 (23). According to Matthew et al. (2 ) only the 13-LOOH is decomposed into Cg- and C-j2 components by the lyase-system E2 This is consistent with the results of Kazeniac et Hall (2 ) who demonstrated the formation of ( ) -2-hexenal, ( )-3-hexenal and ( )-3-hexen-1-ol from linolenic acid in tomato homogenates. 

HETE and 5-HPETE can also be produced in incubations of arachidonic acid with the lipoxygenase in potato and tomato [213,214]. 

These enzymes (e.g., lipoxygenases, polyphenol oxidases, peroxidases) also occur in the tomato plant and are locally and/or systemically inducible, as a result of infection by pathogens (49,53,55,58-62). It should follow that they are also inducible by insect-feeding damage such as that inflicted by H. zea or S. exigua. and amplify the antinutritive defense. 

Polyphenol Oxidase. Peroxidase, and Lipoxygenase in Resistance. Polyphenol oxidase in conjunction with chlorogenic acid as a substrate has the potential to reduce the ability of larval H. zea and S. exigua to utilize dietary protein. For example, alkylation of casein in artificial diet (at 1.0% wwt) by PPO (from mushroom or tomato plant) and chlorogenic acid, at levels commensurate with that found in tomato foliage, inhibits the growth of both larval species by up to 70% (Table 1). Rutin is a very poor substrate for mushroom tyrosinase and tomato PPO (79 unpubl data), and hence,... 

Relative growth - mg/day/mg of larva lipoxygenase, peroxidase, and polyphenoloxidase were added to diet at activities corresponding to that found in tomato foliage rutin and chlorogenic acid at 3.5 mM/kg diet wwt. Significant differences between means within a column, based 95% confidence intervals from ANOVA, are shown by different letters. PPO - 0.100 O.D./min/gm diet wwt. POD - 27.0 O.D./min/gm diet wwt. 

We have the least information about the antinutritive effects of lipoxygenase (LOX). Experiments (Table IV) show that the nutritive value of protein to H. zea is reduced by treatment with LOX and linoleic acid (52% reduction in growth). Tomato foliage contains significant quantities of LOX activity and linoleic acid has been shown to be covalently bound to protein both in vitro and in planta (unpubl. data). Studies are underway to determine which amino acids are preferentially destroyed. Also, preliminary studies with foliage demonstrate that copious quantities of malondialdehyde are generated in crushed foliage the antinutritional effects of this Schiff base former are as yet undetermined. 

Ties R Barringer S. Influence of lipid eontent and lipoxygenase on flavour volatiles in the tomato peel and flesh. J Food Sci. 2013 77 C830-C7. 

EFFECT OF y-IRRADIATION ON TOMATO FRUIT RIPENESS WITH SPECIAL REGARD TO LIPOXYGENASE ACTIVITY, CAROTENOID CONTENT AND ANTIOXIDATION POTENCY... 

The purpose of the present study was to investigate the effects of low and relatively high doses of y-irradiation on some physiological orders of tomato fruit ripeness (pigmentation, bioantioxidant content and lipoxygenase activity). 

Daood, H.G. and Biacs, P.A. (1988) Some properties of tomato fruit lipoxygenase, Acta Aliment. 17, 53-65. 

Chen, G.P., etal. (2004) Identification of a specific isoform of tomato lipoxygenase (TomloxC) involved in the generation of fatty acid-derived flavor compounds. Plant Physiol. 136, 2641-2651... 

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