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22 Cards in this Set

  • Front
  • Back
Where does fatty acid synthesis occur?
-in the cytoplasm of most cells
*liver is major site
What are the three enzyme systems of fatty acid synthesis?
1) biosynthesis of Palmitate from Acetyl-CoA
2) Chain elongation starting with palmitate
3) desaturation
List the intermediates for the biosynthesis of Plamitate.
-acetyl-CoA to Acetyl-ACP to Acetyl synthase
-acetyl-CoA to malonyl-CoA to Malonyl-ACP
-both paths become Acetoacetyl-ACP, then B-3-Hydroxybutyryl-ACP then Crotonyl-ACP then Butytyl-ACP then Palmitoyl-ACP and lastly Palmitate
What are the starting and end materials for Palmitate synthesis?
-Acetyl-CoA and Palmitate
Once the two paths merge, what is the 1, 2, 3, and 4th things to happen in Fatty Acid Synthesis?
-first reduction
-second reduction
*further rounds of FA synthesis
What controls Fatty Acid Metabolism?
-hormones such as Glucagon, epinephrine, and insulin
What are the improtant control points?
-release of fatty acids from adipocytes
-regulation of Carnitine Acyltransferase in the liver
-regulation of acetyl-CoA carboxylase
What does high insulin do after a meal?
-inhibits breakdown of stored fats and stimulates the synthesis of malonyl-CoA
What does malonyl-CoA inhibit?
carnitine acyl transferase I so fatty acids are not oxidized
When fasting, what happens?
-insulin level drops releasing breakdown of fats
-epinephrine and glucagon increase
What does the presence of citrate do to Acetyl-CoAcarboxylase?
What inhibits the active enzyme?
-polymerizes it to a filamentous form of 4-8 million wt!
-polymer is active
What are the shapes of elongation intermediates?
-CoA esters
What desaturates (forms double bond) Acyl-CoA molecules?
Where does desaturation of FA occur?
-NADH and O2
-on the ER
What are the most common fatty acids in animal lipids?
-oleic acid
-palmitoleic acid
What are Fatty Acyl Desaturates?
-membrane bound flavoproteins which require Cytochrome B5 and O2
What are essential fatty acids?
What can they be used for?
-fatty acids that the body can't make (ex; mammals can't make double bonds beyond 9th carbon so linoleic acid can't be made)
-can be used to synthesize polyunsaturated fatty acids
How do you synthesize Arachidonic acid?
-from linoleic acid
-Linoeoyl CoA to y-Linoeoyl CoA to Eicosatrienoyl CoA to Arachidonyl CoA
*all cis forms
What are isoprenoids called?
What is the first step of terpenoid synthesis that occurs in all organisms?
-Acteyl-CoA to Isopentenyl Pyrophosphate (IPP)
What are the next 3 steps to synthesize Cholesterol?
-IPP to Squalene
-Cyclization of Squalene
-Conversion of Lanesterol to Cholesterol
What are the steps to get from Actyl-CoA to IPP?
-acetyl-CoA to Acetoacetyl-Coa
-to HMG-Coa
-to Mevalonic acid
-to Pyrophosphomevalonic acid -and finally to IPP
How does Squalene get to cholesterol?
-squalene to Lanosterol which goes to cholesterol