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29 Cards in this Set

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What breaks down triglycerides (fats)?
Where does this occur?
-pancreatic lipase
*in small intestine
After being broken down in small intestine, what happens?
-fragments transported into enterocytes and resynthesized
-combined with lipoprotein to make chylomicrons which are released to lymph
-passed to blood and carried through the body
Who showed that fatty acids are broken down into 2 carbon pieces?
-Knoop
Where are the enzymes for Beta Oxidation located?
What does this mean?
-in mitochondria
-FA must be transported into the mitochondria for Beta oxidation
What are fatty acids used for (activation)?
-only used as Acyl-CoA derivatives for Beta-oxidation and triglyceride synthesis
What makes the fatty acid derivatives used in B-oxidation?
-Thiokinase
AKA: Acyl-CoA synthetase
What is AMP cycling?
Describe energy requirement.
How do you get phosphate to use for this?
-turning AMP back into ATP
-it takes two ATP to convert AMP back to one ATP molecule
-pyrophosphate is quickly split into phosphate by phyrophosphatase in the cell
What is a carnitine shuttle for?
Where is it located?
-a specialized carrier for transporting fatty acids which have undergone a CoA derivative conversion into the mitochondria
-located in MIM
After FA pass through carnitine shuttle, what happens to them?
-two carbons are removed from corboxyl end forming acetyl-CoA
What is the main (important) reason for having the carnitine shuttle?
-it allows for fatty acids to be used as energy sources which reduces them from the body
How much energy is created from B-oxidation?
-108 ATP, less 2 ATP for formation of CoA derivatives leaves 106 ATP!!
What things make odd-chain fatty acids?
What is different from even-chains undergoing B-oxidation?
-plants and microorganisms
-after beta-oxidation, propionyl-CoA is last result
What is problematic about propionyl-CoA being formed at end of B-oxidation in plants and microorganisms?
-can not be handled as Acetyl-CoA is for the TCA cycle or other synthetic pathways
What must occur with Propionyl-CoA to make it usable?
-it is converted to Succinyl-CoA and continues through 3 steps of TCA cycle to give L-Malate
-Malic enzyme then cleaves it to give pyruvate which can enter the TCA cycle
What are the steps in converting Propionyl-CoA to Succinyl-CoA?
-Propionyl-CoA to D-methylmalonyl-CoA (Propionyl-CoA Carboxylase) to L-methylmalonyl-CoA (Methylmalony-CoA Recemase) to Succinyl-CoA (methylmalonyl-CoA Mutase)
What needs to be used in oxidation of unsaturated fatty acids?
Why?
-Enoyl-CoA isomerase
-2,4-Dienoyl-CoA Reductase
*double bonds often not in spot for B-oxidation
Where does Alph-Oxidation occur?
-in microorganisms such as in a rumen
Describe alpha-oxidation.
-chlorophyll contains phytol which is oxidized to phytanic acid
-phytanic acid to Pristanic acid
-pristanic acid treated with Acyl-CoA synthase and is allowed to enter B-oxidation
Why can't phytanic acid enter B-oxidation without being converted to pristanic acid?
-it is blocked at the Beta position
Where does most Acetyl-CoA go from glycolysis and Beta-oxidation?
-TCA cycle
For the Acetyl-CoA that doesn't enter the TCA cycle, where else can it go?
-to make ketone bodies
What can ketones be used for?
-used to be thought of as waste, but now used for energy source for the heart, kidney, and brain
What is importnat abotu ketones in the body?
-they can be converted back to Acetyl-CoA for the TCA cycle!
What are some diseases of Fatty Acid Oxidation?
-Propionic Acidemia
-Propionic Acidosis
-Refsum's Disease
-Acyl-CoA Dehydrogenase Deficiencies
What happens in Propionic Acidemia?
-can not convert propionyl-CoA to D-methlmalonyl-CoA
-disorder of odd chain and brnached chain fatty acid metabolism (results in the build-up of propoinic acid)
-vomiting, dehydration, severe metabolic acidosis
What does propionic acidosis result from?
-lack of Propionyl-CoA carboxyolase.
Describe Refsum's Disease
-caused by a lack of alpha-hydroxylating activity for phytanic acid
-leads to nerve damage from the build-up of phytanic acid
-treated by avoiding foods with phytanic acid
What are the three acyl DH enzymes in mitochondrion?
-Long-chain Acyl DH
-Medium
-Small
When does Medium chain Acyl-CoA DH deficiency show itself?
Symptoms?
-within first two years of life
-after fasting 12 hours you get vomiting, lethargy, and even coma