Loading Pathway...
Error: Pathway image not found.
Hide
Pathway Description
Arachidonic Acid Metabolism
Homo sapiens
Metabolic Pathway
This pathway describes the production and subsequent metabolism of arachidonic acid, an omega-6 fatty acid. In resting cells arachidonic acid is present in the phospholipids (especially phosphatidylethanolamine and phosphatidylcholine) of membranes of the body’s cells, and is particularly abundant in the brain. Typically a receptor-dependent event, requiring a transducing G protein, initiates phospholipid hydrolysis and releases the fatty acid into the intracellular medium. Three enzymes mediate this deacylation reaction including phospholipase A2 (PLA2), phospholipase C (PLC), and phospholipase D (PLD). Once released, free arachidonate has three possible fates: 1) reincorporation into phospholipids, 2) diffusion outside the cell, and 3) metabolism. Arachidonate metabolism is carried out by three distinct enzyme classes: cyclooxygenases, lipoxygenases, and cytochrome P450’s. Specifically, the enzymes cyclooxygenase and peroxidase lead to the synthesis of prostaglandin H2, which in turn is used to produce the prostaglandins, prostacyclin, and thromboxanes. The enzyme 5-lipoxygenase leads to 5-HPETE, which in turn is used to produce the leukotrienes, hydroxyeicosatetraenoic acids (HETEs) and lipoxins. Some arachidonic acid is converted into midchain HETEs, omega-chain HETEs, dihydroxyeicosatrienoic acids (DHETs), and epoxyeicosatrienoic acids (EETs) by cytochrome P450 epoxygenase hydroxylase activity. Several products of these pathways act within neurons to modulate the activities of ion channels, protein kinases, ion pumps, and neurotransmitter uptake systems, affecting processes such as cellular proliferation, inflammation, and hemostasis. The newly formed eicosanoids may also exit the cell of origin and bind to G-protein-coupled receptors present on nearby neurons or glial cells.
References
Arachidonic Acid Metabolism References
Lehninger, A.L. Lehninger principles of biochemistry (4th ed.) (2005). New York: W.H Freeman.
Vance, D.E., and Vance, J.E. Biochemistry of lipids, lipoproteins, and membranes (4th ed.) (2002) Amsterdam; Boston: Elsevier.
Salway, J.G. Metabolism at a glance (3rd ed.) (2004). Alden, Mass.: Blackwell Pub.
Kroetz DL, Zeldin DC: Cytochrome P450 pathways of arachidonic acid metabolism. Curr Opin Lipidol. 2002 Jun;13(3):273-83.
Pubmed: 12045397
Zeldin DC: Epoxygenase pathways of arachidonic acid metabolism. J Biol Chem. 2001 Sep 28;276(39):36059-62. doi: 10.1074/jbc.R100030200. Epub 2001 Jul 12.
Pubmed: 11451964
Ondrey FG: Arachidonic acid metabolism: a primer for head and neck surgeons. Head Neck. 1998 Jul;20(4):334-49.
Pubmed: 9588707
Sigal E: The molecular biology of mammalian arachidonic acid metabolism. Am J Physiol. 1991 Feb;260(2 Pt 1):L13-28. doi: 10.1152/ajplung.1991.260.2.L13.
Pubmed: 1899973
Highlighted elements will appear in red.
Highlight Compounds
Highlight Proteins
Enter relative concentration values (without units). Elements will be highlighted in a color gradient where red = lowest concentration and green = highest concentration. For the best results, view the pathway in Black and White.
Visualize Compound Data
Visualize Protein Data
Downloads
Settings