Oxylipins Formation Pathways Quiz

LOX enzymes = Formation of fatty acid hydroperoxides or endoperoxides COX enzymes = Initiation of oxylipin biosynthesis by dioxygen-dependent oxidation Cytochrome P450 epoxygenase = Oxidize double bonds with epoxide formation or saturated carbons forming alcohols Heme-dependent fatty acid oxygenases = Involvement in oxylipin biosynthesis in plants and fungi

Plants = Production of oxylipins through lipoxygenases and heme-dependent fatty acid oxygenases Animals = Synthesis of oxylipins through lipoxygenases and cyclooxygenases Fungi = Formation of oxylipins via lipoxygenases and heme-dependent fatty acid oxygenases Bacteria = Limited or no significant role in the production of oxylipins

Dioxygenases = Initiate the biosynthesis of oxylipins through oxygen-dependent oxidation of fatty acids Monooxygenases = Oxidize double bonds with epoxide formation or saturated carbons forming alcohols in oxylipin biosynthesis Non-enzymatic autoxidative processes = Contribute to oxylipin formation by producing phytoprostanes and isoprostanes Enzymatic metabolism = Metabolize oxylipins into secondary products with strong biological activity

<p>Oxylipins are not stored in tissues = Formed on demand by liberation of precursor fatty acids from esterified forms Oxylipins are stored in tissues = Readily available for immediate use upon demand Oxylipins are primarily synthesized in advance and stored = Stored in specialized organelles for rapid release when needed Oxylipins are synthesized and stored in the same cellular compartment = Stored in lipid droplets for long-term storage and utilization</p> Signup and view all the answers

<p>Leukotrienes B4 and C4 = Proinflammatory effects Resolvins and protectins = Antiinflammatory effects Linoleic acid oxylipins = Associated with atherosclerosis, non-alcoholic fatty liver disease, and Alzheimer's disease Eicosapentaenoic acid (EPA)-derived and docosahexaenoic acid (DHA)-derived oxylipins = Anti-inflammatory and vasodilatory effects</p> Signup and view all the answers

<p>CYP5A1 (thromboxane synthase) = Involved in smooth muscle regulation in vasculature and myometrium CYP8A1 (prostacyclin synthase) = Involved in smooth muscle regulation in vasculature and myometrium CYP74 family of hydroperoxide-metabolizing enzymes = Involved in control of ontogenesis, reproductive processes, and resistance to microbial pathogens C18 and C20 polyenoic fatty acids = Major precursors of oxylipins in plants and animals</p> Signup and view all the answers

<p>Plant oxylipins = Mainly involved in control of ontogenesis, reproductive processes, and resistance to microbial pathogens Animal oxylipins (eicosanoids) = Have potent and often opposing effects on smooth muscle and blood platelets Most oxylipins in the body = Derived from linoleic acid or alpha-linolenic acid Omega-6 fatty acid-derived oxylipins = More pro-inflammatory, vasoconstrictive, and proliferative than those derived from omega-3 fatty acids</p> Signup and view all the answers

<p>3 grams daily of DHA compared with placebo (olive oil) given for 91 days = Nearly tripled the DHA in red blood cells while reducing oxylipins in those cells Both groups given Vitamin C (ascorbyl palmitate) and Vitamin E (mixed tocopherol) supplements = Given in the clinical trial of men with high triglycerides Lowering dietary linoleic acid = Results in fewer linoleic acid oxylipins in humans Centenarians = Have shown reduced levels of linoleic acid oxylipins in their blood circulation</p> Signup and view all the answers