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23 Cards in this Set
- Front
- Back
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Linoleic Acid -
what is the formula thing, what type of acid is it, what is it a precursor of |
18:2 (9,12)
w-6 precursor of arachidonic acid (precursor of prostaglandins), structural |
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Linolenic Acid -
what is the formula thing, what type of acid is it, what is it a precursor of |
18:3 (9,12,15)
w-3 precursor of other w-3 FAs, structural |
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What are 3 functions of FA synthesis?
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convert carbs and AAs into TAGs to store until needed during fasting
FAs in lipids of membranes precursors of eicanosoids (lipid hormones) |
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when are FA synthesize?
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when we have excess calories in diet
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where does FA synthesis occur?
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liver
also adipose tissue (muscle too but used right away) |
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what is the major source of carbons for FA synthesis
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dietary carbs
also amino acids, TCA cycle intermediates |
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How long are FA in milk?
why? |
4-10 C long
because are easily absorbed > dont require special mechanism to be absorbed in GI tract and transported to mito which is an advantage to newborns and a good source for metabolic energy |
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when is arachidonic acid (w-6) essential?
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if linoleic acid is deficient in the diet
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structural lipids and TAG FAs have at least how many Cs?
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16
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What disease inhibits lipogenesis?
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Type 1 Diabetes
insulin activates the rate-limiting enzyme of FA synthesis(acetyl CoA carboxylase) |
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where are FA and precursors synthesized?
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acetyl Co A is synthesized in mitochondria
glucose > pyruvate > mito > acetyl coA via pyruvate dehydrogenase and OAA via pyruvate carboxylase > citrate citrate can go out to cytoplasm to be converted to FA |
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What 2 enzymes are requires for FA synthesis
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acetyl coA carboxylase (catalyzes rate limiting stem - synthesis of malonyl coA)
FA synthase (cytoplasmic multifunctional enzyme, acyl carrier protein domain with phosphopantetheine covalently linked) |
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What does Acetyl coA need when synthesizing malonyl coA?
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BIOTIN
and ATP |
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What is the allosteric, hormonal, long term regulation of acetyl coA carboxylase?
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allosteric:
high citrate > aggregation > activation end product inhibition by palmitoyl CoA insulin activates acetyl coA carboxylase, dephosphorulation promotes polymerization phosphorylation inhibits acetyl coA carboxylase (promotes dissociation) long germ: high carbs/ low fat diet increases enzyme expression starved or high fat/low carb decrease enzyme expression **on level of transcription |
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How does AMP activated Kinase (AMPK) regulate acetyl coA carboxylase?
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important in tissues that dont significantly make FAs (skeletal and cardiac muscles)
low ATP= high AMP > phosphorylates acetyl coA carboxylase > inhibites > decreased malonyl coA production (malonyl coA is an inhibitor of FA oxidation) > FA released from inhibition > increased ATP profuction |
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what makes fatty acid synthase flexible?
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phosphopantetheine
is covalently liked to ACP domain its long flecible arm allows it to move from one active site to another within the complex |
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what is needed to synthesize FAs?
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ATP, NADPH, acetyl coA
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What is the major source fo NADPH for FA synthesis?
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pentose P pathway
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after FA synthesis, what enzyme is needed to synethesize palmitate?
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palmitoyl thioesterase
and H2O |
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Where does FA elongation occur?
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in ER and mitochondria
palmitoyl coA is the substrate for fatty acid eloncase |
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where does desaturation occur?
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in the ER
catalyzed by mized function oxidases and require NADH and O2 -palmitic (16:0) > palmitoleic acid (16:1)9 |
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what are certain FA essential?
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humans cant introduce double bonds from carbone 10 to w end of chain, need polyunsaturated linoleic and linolenic acids in diet
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What is deficient in respiratory distress syndrome?
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phosphatidylcholine
produced by granular pneuumocytes and is the major component of lung surfactant that prevents alveolar collapse premature infant does not produce enfough serfactant > lmajor cause of death in newborn of people exposed to a lot of dust |
