5-lipoxygenase localization

Lipoprotein Metabolism Lipoproteins Liposomes 5-Lipoxygenase Lipoxygenases Lithocholic Acid Local Anaesthetics Locus... 

Another mechanism that potentially contributes to clove oil s effects is inhibition of prostaglandin synthesis through both cyclooxygenase and lipoxygenase pathways (Tyler 1994). Accordingly, local injections of clove oil supressed joint swelling in arthritic rats (Sharma et al. 1994). 

Leprosy, chemotherapy, 20 (1983) 1 Ligand-receptor binding, 23 (1986) 41 Linear free energy, 10 (1974) 205 5-Lipoxygenase inhibitors and their antiinflammatory activities, 29 (1992) 1 Literature of medicinal chemistry, 6 (1969) 66 Lithium, medicinal use of, 11 (1975) 193 Local anaesthetics, 3 (1963) 332 Lonidamine and related compounds, 21 (1984)111... 

Disturbances in lipid metabolism occur in the skin in psoriasis. Increased phospholipase A2 activity is seen in lesional and nonlesional skin, while phospholipase C activity is elevated in lesional skin.183-184 Increased elongase activity is also observed in psoriatic epidermis. A local increase in AA occurs, and this appears to be preferentially metabolized by the lipoxygenases, resulting in a marked increase in 12-HETE and LTB4, while there appears to be a relative or absolute reduction in metabolism by the COX pathway.185 Leukotriene B4 is a very potent chemoattractant, and topical application causes epidermal hyperproliferation in addition to neutrophil microabscesses.186 A defective transmembranous cell-signaling system is also suggested by elevation of both IP3 and DAG in the psoriatic plaque.187... 

Besides proteases and nucleases some lipoxygenases [140,141] are also located in the cytosol of cells [142]. Lipoxygenases react with polyunsaturated fatty acids (PUFAs), containing one or several double allylically activated CHa groups (-CH=CH-CH2-CH=CH-) [140,141]. PUFAs are mainly localized at position 2 of a phospholipide [143]. This is exactly the site where phospholipases Aa - liberated by cell injury -attack phospholipides. 

The main response of plants to wounding either to mechanically injury but also by pathogen attack is activation of lipases, followed by those of lipoxygenases as outlined above. Lipoxygenases remove from PUFAs a hydrogen atom localized at a double allylically activated methylene group, forming a mesomeric radical (Scheme 2). 

In contrast to most lipoxygenases, which require free PUFAs as substrates, radicals are able to attack any compound possessing a -CH=CH-CH2-CH=CH-group, including PUFAs esterified to sterols or phospholipids [236]. The latter are localized in cell walls and consequently radicals are able to damage adjacent cells. 

In our calculations [47], we treated the net hydrogen transfer reaction catalyzed by lipoxygenase as a PCET mechanism, as illustrated in Fig. 16.9. Quantum mechanical calculations indicate that the electron transfers from the n system of the linoleic acid to an orbital localized on the Fe(III) center, and the proton transfers... 

The eicosanoids are locally active hormones (autocoids) that are derived from precursor polyunsaturated fatty acids. The rate-limiting step in the synthesis of eicosanoids is the phospholipase-regulated release of arachidonic add from membranes. Arachi-donic acid metabolism may follow one of three possible pathways. In the first, the cydooxygenase- peroxidase pathway leads to the formation of the prostenoids - prostaglandins and thromboxanes. In the second, the lipoxygenase pathway yields the leuko-trienes and lipoxins. A third pathway, the cytochrome P-450 mono oxygenase pathway is also involved in the metabolism of arachidonic add. 

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. 

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