Fatty Acid and Triacylglycerol Metabolism Flashcards
What are the two main sites of fatty acid de novo synthesis?
1) Liver after a carbohydrate rich meal
2) Lactating mammary gland
What can be achieved by fatty acid de novo synthesis in the liver after a carbohydrate rich meal?
Fatty acid de novo synthesis in the liver reduces the high blood glucose level
after a carbohydrate-rich mean and it also provides fatty acids for eventual
storage in TAGs in fat cells.
Which metabolic condition leads to high citrate levels in liver mitochondria?
A high carbohydrate diet leads to increased citrate in liver mitochondria
What happens to the citrate in liver mitochondria after a carb rich meal
High citrate levels in liver mitochondria lead to transfer of citrate into the cytosol
Describe the cellular location of citrate lyase and describe the irreversible reaction catalyzed by this enzyme.
-Citrate lyase is found in cytosol.
-Citrate and CoA and ATP are the substrates and products are acetyl CoA ,
oxaloacetate , ADP and Pi
Describe the cellular location and the reaction catalyzed by the malic enzyme.
- The malic enzyme is found in liver cytosol.
- Malate and NADP+ are substrates and products are pyruvate, CO2 and NADPH
What is the dietary precursor to arachidonic acid?
Linoleic acid
Biosynthesis of fatty acids most likely occurs in which state?
Well-fed state
Where does Acetyl CoA produced in mitochondria come from?
- oxidation of pyruvate (PDH complex)
- Degradation of fatty acids
- Degradation of ketone bodies
- Degradation of amino acids
What happens when ATP is high in the mitochondria which causes Acetyl CoA to be converted to citrate?
Isocitrate dehydrogenase is inhibited
What is Acetyl CoA converted to for transport in the cytosol?
Citrate
Once in the cytosol, what enzyme converts Citrate into Acetyl CoA and Oxaloacetate?
ATP-Citrate lyase
Which enzyme produces NADPH in order to be used in Fatty Acid synthesis?
Malic enzyme
converts malate to pyruvate
Which enzyme catalyzes the first committed step of fatty acid biosynthesis?
Acetyl CoA Carboxylase (ACC)
What is the rate-limiting enzyme for fatty acid synthesis?
Acetyl-CoA Carboxylase
Which cofactor does Acetyl CoA Carboxylase need?
Biotin
Acetyl CoA Carboxylase requires how many ATP molecules per malonyl-coA formed?
1 ATP
The enzyme Acetyl CoA Carboxylase converts _____ to _____
Acetyl CoA
Malonyl CoA