Biochem: Fatty Acid Breakdown

Front 1

What breaks down triglycerides (fats)?
Where does this occur?

Back 1

-pancreatic lipase
*in small intestine

Front 2

After being broken down in small intestine, what happens?

Back 2

-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

Front 3

Who showed that fatty acids are broken down into 2 carbon pieces?

Back 3

-Knoop

Front 4

Where are the enzymes for Beta Oxidation located?
What does this mean?

Back 4

-in mitochondria
-FA must be transported into the mitochondria for Beta oxidation

Front 5

What are fatty acids used for (activation)?

Back 5

-only used as Acyl-CoA derivatives for Beta-oxidation and triglyceride synthesis

Front 6

What makes the fatty acid derivatives used in B-oxidation?

Back 6

-Thiokinase
AKA: Acyl-CoA synthetase

Front 7

What is AMP cycling?
Describe energy requirement.
How do you get phosphate to use for this?

Back 7

-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

Front 8

What is a carnitine shuttle for?
Where is it located?

Back 8

-a specialized carrier for transporting fatty acids which have undergone a CoA derivative conversion into the mitochondria
-located in MIM

Front 9

After FA pass through carnitine shuttle, what happens to them?

Back 9

-two carbons are removed from corboxyl end forming acetyl-CoA

Front 10

What is the main (important) reason for having the carnitine shuttle?

Back 10

-it allows for fatty acids to be used as energy sources which reduces them from the body

Front 11

How much energy is created from B-oxidation?

Back 11

-108 ATP, less 2 ATP for formation of CoA derivatives leaves 106 ATP!!

Front 12

What things make odd-chain fatty acids?
What is different from even-chains undergoing B-oxidation?

Back 12

-plants and microorganisms
-after beta-oxidation, propionyl-CoA is last result

Front 13

What is problematic about propionyl-CoA being formed at end of B-oxidation in plants and microorganisms?

Back 13

-can not be handled as Acetyl-CoA is for the TCA cycle or other synthetic pathways

Front 14

What must occur with Propionyl-CoA to make it usable?

Back 14

-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

Front 15

What are the steps in converting Propionyl-CoA to Succinyl-CoA?

Back 15

-Propionyl-CoA to D-methylmalonyl-CoA (Propionyl-CoA Carboxylase) to L-methylmalonyl-CoA (Methylmalony-CoA Recemase) to Succinyl-CoA (methylmalonyl-CoA Mutase)

Front 16

What needs to be used in oxidation of unsaturated fatty acids?
Why?

Back 16

-Enoyl-CoA isomerase
-2,4-Dienoyl-CoA Reductase
*double bonds often not in spot for B-oxidation

Front 17

Where does Alph-Oxidation occur?

Back 17

-in microorganisms such as in a rumen

Front 18

Describe alpha-oxidation.

Back 18

-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

Front 19

Why can't phytanic acid enter B-oxidation without being converted to pristanic acid?

Back 19

-it is blocked at the Beta position

Front 20

Where does most Acetyl-CoA go from glycolysis and Beta-oxidation?

Back 20

-TCA cycle

Front 21

For the Acetyl-CoA that doesn't enter the TCA cycle, where else can it go?

Back 21

-to make ketone bodies

Front 22

What can ketones be used for?

Back 22

-used to be thought of as waste, but now used for energy source for the heart, kidney, and brain

Front 23

What is importnat abotu ketones in the body?

Back 23

-they can be converted back to Acetyl-CoA for the TCA cycle!

Front 24

What are some diseases of Fatty Acid Oxidation?

Back 24

-Propionic Acidemia
-Propionic Acidosis
-Refsum's Disease
-Acyl-CoA Dehydrogenase Deficiencies

Front 25

What happens in Propionic Acidemia?

Back 25

-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

Front 26

What does propionic acidosis result from?

Back 26

-lack of Propionyl-CoA carboxyolase.

Front 27

Describe Refsum's Disease

Back 27

-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

Front 28

What are the three acyl DH enzymes in mitochondrion?

Back 28

-Long-chain Acyl DH
-Medium
-Small

Front 29

When does Medium chain Acyl-CoA DH deficiency show itself?
Symptoms?

Back 29

-within first two years of life
-after fasting 12 hours you get vomiting, lethargy, and even coma