Lecture 42: Fatty Acid Oxidation Flashcards
Under what physiological conditions does FAO become the predominant source of energy?
- heart muscle
- extended periods of exercise
- periods of starvation
- diabetic patients in whom glucose
Describe the difference between long distance versus short distance runners.
Long distance: lean because of oxidation of fatty acids
short distance: muscular and break down glycogen
List some problems that fatty acid oxidation defects may be involved with.
- symptoms of Reyes-like syndrome
- cardiomyopathy
- hypotonia
- hypoglycemia
- developmental delay
- SIDS
Release of fatty acids is done through ______.
hormonal action
Triacylglycerol lipase functions only on triacylglycerol making it into what compound?
diacylglycerol
T/ F: Triacylglycerol lipase is active when dephosphorylated.
False. The triacylglycerol is phosphorylated when activated.
What does insulin do to lipid synthesis?
It enhances lipid synthesis by increasing the synthesis of glycolytic enzymes and enzymes that are involved in fatty acid synthesis (acyl CoA).
What are lipolysis inducing hormones?
Epinephrine
glucagon
adrenocorticotropic hormones
Fatty acids are activated by which enzyme?
Acyl CoA syntthetase
Where is Acyl CoA present?
- cytosol
2. outer mitochondrial membrane
T/F: Acyl CoA can travel through the outer mitochondrial membrane but not the inner mitochondrial membrane.
True.
Which enzyme is used to make Acyl carnitine, which can travel through the inner mitochondrial membrane?
carnitine acyltransferase I (it is the rate limiting enzyme)
Acyl carnitine is coverted into acyl CoA by which enzyme?
Carnitine acyltransferase II
What does carnitine acylcaritine translocase do?
It transports Acyl carnitine through the inner mitochondrial membrane.
What are three enzymes that are involved in the first step of beta oxidation pathway?
LCAD
MCAD
SCAD
What is the ultimate purpose of the beta oxidation pathway?
oxidize beta carbon
remove 2 carbons in the form of acetyl CoA
2 carbon shorter acyl CoA
Which enzyme do SIDS kids have a deficiency in?
MCAD
Which do you get more energy from: unsaturated or saturated fatty acids?
saturated releases more energy because no double bonds so FADH2 produced every cycle
What is the equation used to know the number of acetyl CoA from a fatty acid?
no. of compounds/2
How do you find the no. of FADH2 and NADH?
No of C-2/2
remember: for FADH2, subtract one for every double bond in the original compound
When you have odd numbered carbon fatty acids, what kind of CoA is formed?
Propionyl CoA
What happens to propionyl CoA?
It becomes succinyl CoA and enters the TCA cycle
Why do you form ketone bodies?
They are formed due to excessive oxidation of fatty acids and it produces a lot of acetyl CoA. It is caused by diabetes/ periods of starvation.
What are the two (or three) ketone bodies?
Acetoacetate
D- beta- hydroxybutyrate
(acetone)
What is a ketone body?
It is a substance that is used to produce energy
Where in the body are ketone bodies used?
They can be used by the heart, brain and muscle for energy.
T/F: The concentration of ketone bodies in the plasma should be zero normally.
False. The concentration of ketone bodies in the plasma will never be zero. It is present in low concentrations and is elevated when starving/ have diabetes.
CPT1 (Carnitine palmoitoyl transferase I) is another name for which enzyme?
Carnitine acyltransferase I
What compound inhibits carnitine acyltransferase I or carnitine palmoitoyl transferase I?
malonyl CoA which is a product of fatty acid synthesis
Which hormones regulate fatty acid oxidation?
Glucagon (increae)
Epinepherine (increase)
insulin (decrease)
these affect triacyl glycerol (aka hormone sensitive lipase)
How can you correct carnitine deficiency?
give carnitine in the diet
How is fattyacyl CoA synthetase deficiency or mutations in acyl carnitine- carnitine mutations corrected?
It is corrected by giving C8, C10 fatty acids because they are free fatty acids that do not need to be converted to acyl carnitine to get through the inner mitochondrial membrane.
