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14 Cards in this Set
- Front
- Back
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Glycerophospholipids
What is it? What does it consist of? Linkages? Simplest glycerophospholipid? |
-Phospholipids derived from glycerol are called glycerophospholipids or phosphoglycerides
-A glycerophospholipid consists of a glycerol backbone, two fatty acid chains, and a phosphorylated alcohol -In the majority of glycerophospholipids, the hydroxyl groups at C-1 and C-2 of glycerol are esterified to the carboxyl groups of two fatty acid chains (an ESTER linkage is formed that liberates a water molecule). The resulting compound, called phosphatidic acid (or phosphatidate in its deprotonated form) or diacylglycerol-3-phosphate, is the simplest glycerophospholipid. -While only small amounts of phosphatidic acid are present in membranes, it is a key intermediate in the biosynthesis of the other glycerophospholipids |
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Ether phospholipid
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-Glycerophospholipids in which the fatty acid at position C1 of glycerol is attached with an ETHER linkage (normally ester linkage)
-Ethers are resistant to LIPASES. -eg. Plasmalogen (ether linked alkene) -eg. Platelet-activating factor (ether linked alkane) |
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Plasmalogen
-what is it -where is it found |
-Plasmalogens are vinyl ether phospholipids, with an unsaturated double bond between C1 and C2 of the alkene chain
-Plasmalogens are abundant in the membranes of cardiac muscle tissue as well as many single cell organisms |
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Plasmalogen
-what is it -where is it found |
-Plasmalogens are vinyl ether phospholipids, with an unsaturated double bond between C1 and C2 of the alkene chain
-Plasmalogens are abundant in the membranes of cardiac muscle tissue as well as many single cell organisms -plasmologen here has choline head group .. Can also have other head groups (ethanolamine, serine) dunno why cells have evolved to have ether linked phospholipids over more traditional ones with ester linkages -Ethers are resistant to LIPASES. -BIOMARKER: In some highly metastatic cancers plasmalogen levels elevated!!!! |
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Platelet activating factor
-what is it -what does it do? -how does it work? |
-Platelet activating factor is a 1-alkyl-2-acetyl ether analog of phosphatidylcholine
-It promotes the aggregation of platelets and the release of the vasoconstrictor serotonin from platelets -Platelet activating factor also plays an important role in inflammation and the allergic response in a variety of tissues NOTE: 1. ether link 2. ACETYL ESTER AT CARBON 2 -->by having acetyl group here, INCREASE SOLUBILITY 10^-10M -->Not massively soluble, but can circulate through body, can bind to cell surface receptor as a ligand, causes platelets to aggregate, release contents of granules, can get involved in mediation of analpthatic shock and innate inflammatory response How it WORKS: acetyl ester gets cleaved off, and you INACTIVATE PLATELT ACTIVATING FACTOR * synthesized in different mechanism than traditional ester linked phospholipids |
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Sphingolipids
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-Lipids derived from sphingosine are called SPHINGOLIPIDS
-sphingosine has a large hydrocarbon tail and a polar region that includes an amino group -The amino group can form an amide bond with the carboxylic group of fatty acids, yielding ceramide. -Sphingomyelin is the only membrane phospholipid not derived from glycerol |
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Eicosaniods
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-The eicosaniods are paracrine hormones derived from polyunsaturated 20-carbon fatty acids, predominanntly arachadonic acid.
-The eicosanoids elicit a variety of effects on a number of vertebrate tissues |
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Composition of lung surfactant
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Complex Mix!
Major components: 1. DPPC (Dipalmitol phosphatidylcholine) 2. PC (unsaturated phosphatidyl choline) 3. PG (phosphatidyl glycerol) Why is this clinically relevant? Infant respiratory distress syndrome ratio of Phosphatidyl choline (used to be called lectinin) to Sphingomyelin in lung surfactant if that ratio is above 2, there is no risk for respiratory distress syndrome further that ratio drops greater the risk for RDS now people also measuring PG (blue in pie chart) --> see it, have productive lung surfactant. Also measure ratio of LIPIDS relative to PROTEIN can relieve problem by introducing lung surfactants premie develops starts producing it naturally and infant is fine. |
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Fetal Lung Surfactant Production
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production of PC only happens towards latter half of pregnancy but sphingomyelin is produced relatively constant throughout if mother is thought to be going into premature labor/premature birth: one of things that gets measures is L/S ratio
ratio of Phosphatidyl choline (used to be called lectinin) to Sphingomyelin in lung surfactant if that ratio is above 2, there is no risk for respiratory distress syndrome further that ratio drops greater the risk for RDS now people also measuring PG (blue in pie chart) --> see it, have productive lung surfactant. Also measure ratio of LIPIDS relative to PROTEIN can relieve problem by introducing lung surfactants premie develops starts producing it naturally and infant is fine. |
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Another name for phosphatidic acid? What would you call it when it's protonated v. deprotonated?
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phosphatidic acid (or phosphatidate in its deprotonated form) or diacylglycerol-3-phosphate, is the simplest glycerophospholipid.
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Review the head groups from MCP
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Do it!
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The only membrane phospholipid not derived from glycerol
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Sphingomyelin is the only membrane phospholipid not derived from glycerol
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What happens to the alveoli during respiration? How are they able to function properly?
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Respiration involves the expansion
& contraction of lung alveoli Alveoli are lined with surfactant --> think of plastic sandwich bag with water in it and then you pour it out -- it sticks together -->now fill with soapy water – it wouldn't stick. The soap decreases the surface tension, so it doesn’t stick. It takes more pressure to expand alveoli without surfactant (>35 fold reduction in force needed with surfactant present) How is this clinically relevant? Infant respiratory distress syndrome |
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L/S ratio
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ratio of Phosphatidyl choline (used to be called lectinin) to Sphingomyelin in lung surfactant
if that ratio is above 2, there is no risk for respiratory distress syndrome further that ratio drops greater the risk for RDS can relieve problem by introducing lung surfactants premie develops starts producing it naturally and infant is fine. |
