Ferrous lipoxygenases seem to be activated through a feedback control mechanism via fatty acid hydroperoxides generated from polyunsaturated fatty acids (PUFAs) by partially existing ferric lipoxygenases. However, during leukotriene synthesis, feedback activation of ferrous 5-lipoxygenase in the presence of arachidonic acid (AA) was not observed. In the present study, we examined the feedback a...

Human peripheral blood polymorphonuclear leukocytes (PMNs) metabolized [14C]arachidonic acid predominantly by lipoxygenase pathways. The major products were 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE) and 15-HETE. These and other lipoxygenase products, including their derived leukotrienes, have been implicated as mediators of inflammatory and allergic reactions. In human platelets, the n...

The 12-lipoxygenase pathway is a key mediator of angiotensin II (Ang II)-induced effects in the adrenal cortex. We also recently demonstrated that Ang II increases 12and 15-lipoxygenase product levels in vascular smooth muscle cells. However, the relation between lipoxygenase activation and Ang II-induced vascular smooth muscle cell hypertrophy is not known. We studied the effects of Ang II and...

The hypersensitive reaction in incompatible wheat-rust interactions is characterized by an increase in lipoxygenase activity detectable as early as 28 h after penetration o f the pathogen. In contrast, lipoxygenase activity in the compatible interaction did not increase until the onset of sporulation. Lipoxygenase activity also increased following treatment o f wheat leaves with an elicitor fra...

5-Lipoxygenase is a key enzyme in the metabolism of arachidonic acid to leukotrienes. The preventive efficacy of 5-lipoxygenase inhibitors against lung tumorigenesis was determined in A/J mice given the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in drinking water from week 0 to week +7. Groups of 25 mice were fed either: acetylsalicylic acid (ASA), a cycloo...

Cloning and sequencing of two cDNAs from mRNA of maturing pea (Pisum sativum) seeds allowed the deduction of the complete amino acid sequence of a lipoxygenase polypeptide which is most similar to that of soya-bean lipoxygenase 2. The predicted Mr of this polypeptide is 97134, and its sequence permits comparisons between the lox2-type and the lox3-type lipoxygenase isoforms from pea and soya be...

Cooxidation activity of highly purified soybean lipoxygenase-2 and -3 was investigated with all-trans-retinoic acid as a co-substrate. Both the isoenzymes rapidly degraded retinoic acid in the presence of linoleic acid, but lipoxygenase-2 had more cooxidation activity than lipoxygenase-3. During cooxidation, 5, 6-epoxyretinoic acid was formed as a major product. HPLC on a chiral phase (Ceramosp...