Formation of a cyclopropyl epoxide via a leukotriene A synthase-related pathway in an anaerobic reaction of soybean lipoxygenase-1 with 15S-hydroperoxyeicosatetraenoic acid: evidence that oxygen access is a determinant of secondary reactions with fatty acid hydroperoxides.

ABSTRACT: The further conversion of an arachidonic acid hydroperoxide to a leukotriene A (LTA) type epoxide by specific lipoxygenase (LOX) enzymes constitutes a key step in inflammatory mediator biosynthesis. Whereas mammalian 5-LOX transforms its primary product (5S-hydroperoxyeicosatetraenoic acid; 5S-HPETE) almost exclusively to LTA(4), the model enzyme, soybean LOX-1, normally produces no detectable leukotrienes and instead further oxygenates its primary product 15S-HPETE to 5,15- and 8,15-dihydroperoxides. Mammalian 15-LOX-1 displays both types of activity. We reasoned that availability of molecular oxygen within the LOX active site favors oxygenation, whereas lack of O(2) promotes LTA epoxide synthesis. To test this, we reacted 15S-HPETE with soybean LOX-1 under anaerobic conditions and identi

SUBMITTER: Zheng Y 

PROVIDER: S-EPMC2859502 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature