Two types of 12-lipoxygenase that catalyze the transformation of arachidonic acid to 12(S)-hydroperoxyeicosatetraenoic acid (12-HPETE) have been previously classified into platelet-type and leukocyte-type categories. Here, we document, for the first time, a molecular characterization of both forms within the same species. The amino acid sequence of the murine platelet 12-lipoxygenase deduced fr...

The effects of various lipoxygenase metabolites of arachidonic acid (AA) were investigated on the growth of freshly isolated human bone marrow mononuclear cells and marrow stromal cell cultures. LTB4, LXA4, LXB4, 12-HETE and 15-HETE (1 microM) decreased [3H]-thymidine incorporation on marrow stromal cell cultures without affecting cell number. Only 12-HETE showed a dose-response effect on [3H]-...

Leukotriene A4 synthase was purified from the cytosolic fraction of murine mast cells. The enzyme converted 5-hydroperoxy-6-trans-8,11,14-cis-icosatetraenoic acid (5-HPETE) to leukotriene A4. This unstable product was identified by demonstration of two epimers of 6-transleukotriene B4, methanol trapping, as well as further transformation to leukotriene B4 by leukotriene A4 hydrolase. Leukotrien...

Objective of the study is to screen for in vitro pharmacological activities of 5-Lipoxygenase and cytotoxicity of using methanolic callus extracts of Biophytum sensitivum. In vitro Brine shrimp lethality assay was carried out according to the method of Meyer et al., (1982) and the lipoxygenase inhibition activity was assayed using photometric method as described by Reddanna et al., (1985). The ...

Lipoxygenases are a class of non-heme iron dioxygenases which catalyze the hydroperoxidation of fatty acids for the biosynthesis of leukotrienes and lipoxins. The structure of the 839-residue soybean lipoxygenase-1 was used as a template to model human 5-, 12-, and 15-lipoxygenases. A distance-based algorithm for placing side chains in a low homology environment (only the four iron ligands were...

Three corn and 2 broccoli cultivars were steam blanched for various times and evaluated for residual enzyme activity. Lipoxygenase was inactivated in 4 min in supersweet corn, while sweet corn required a 6-min blanch; peroxidase was inactivated in 8 min. Inactivation of broccoli lipoxygenase, peroxidase, and cystine lyase was achieved in 90 s. Blanched samples were stored 9 mo at 18 C, then ana...

The gorgonian coral Pseudoplexaura porosa contains a lipoxygenase capable of converting exogenous arachidonic acid into (8R)-8-hydroperoxy-5,9,11,14-eicosatetraenoic acid. The (8R)- (or 8-L-) configuration in this product, opposite to that observed in previously reported 8-lipoxygenase products, was determined unambiguously by comparison of oxidative ozonolysis fragments with authentic malic ac...

This Study using purified tomato fruit chromoplasts has shown significant rates of oxygen consumption even in the absence of external precursors. Oxygen consumption rates increased up to 7-fold when chromoplast samples were incubated for 24 h at room temperature. This increase in oxygen consumption is most likely due to the activation of lipoxygenase in the chromoplasts.

(1) The island of Mayotte, located in the Indian Ocean, possesses remarkable biodiversity. In a previous ethnobotanical study, we already highlighted 69 different plant species used traditional medicine. Among those, 21 were traditionally employed for skin care by local populations. present study aimed to better understand use those plants investigating their vitro biological activities and, mo...