Lipoxygenase subcellular

Timar J, Raso E, Dome B, Li L, Grignon D, Nie D, Honn KV, Hagmann W. Expression, subcellular localization and putative function of platelet-type 12-lipoxygenase in human prostate cancer cell lines of different metastatic potential. Int J Cancer. 87 (2000) 37-43. 

Wang, C. K.P.C. Croft U. Jarlfors D. Hildebrand. Subcellular localization studies indicate that lipoxygenases 1 to 6 are not involved in lipid mobilization during soybean germination. Plant Physiol. 1999,120, 227-235. 

Lipid oxidation in subcellular fractions can be mediated by enzyme systems in muscle microsomes that maintain iron in the ferrous form by reduced nicotinamide adenine dinucleotide (NADH). However, this redox system may not be enzymatic because, unlike lipoxygenase, no specific lipid oxidation products have been identified. Ascorbate and other reducing agents may have the same effects in the presence of heme-protein complexes. On the other hand, the presence of 15-lipoxygenase in chicken muscle may be responsible for oxidative deteriorations in uncooked chicken meat during frozen storage. Phospholipases... 

The subcellular location of lipoxygenase, which might give a clue to its function, has been varied. Vacuoles (8), cytoplasm (9), and protein bodies (9) have been reported as sites of lipoxygenase in some tissues. 

Eicosapentaenoic add (Table 6) is easily incorporated into the cell membrane-bound phospholipids. It is a poor substrate for the cyclooxygenase/hydroper-oxidase enzymatic system, and only very small amounts of endproducts with three double bonds will be formed when compared with the relative effectiveness of arachidonate metabolism. In contrast, dcosapentaenoic add is a preferred substrate for product generation by the S-lipoxygenase in subcellular fractions of human and animal neutrophils [66,87], whereas docosahexaenoic add is also a markedly inferior substrate for leukotriene synthesis. Eicosapentaenoic acid appears to inhibit phospholipase activity, resulting in a decrease of aradiidonic acid release ([67] Fig. 4). Moreover, simultaneously with thromboxane A3 and prostaglandin I3 generation from eicosapentaenoic add, the synthesis of thromboxane A2 and prostacyclin (PGIj) from aradiidonic acid [47] decreases, mainly due to inhibitory effects on PGH synthase activity (Fig. 4). 

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