7. Lipid Metabolism 1 Flashcards
Where does fatty acid synthesis primarily occur (organ)?
The liver
Other than the liver (primary), where might fatty acid synthesis occur? (4)
- Adipose tissue
- Brain
- Kidneys
- Lactating mammary glands
What is the most important substrate in fatty acid synthesis?
What enzyme catalyzes this reaction?
Malonyl CoA
Acetyl CoA Carboxylase
What is the rate limiting step of fatty acid synthesis?
Acetyl CoA Carboxylase
Where is Acetyl CoA synthesized?
In the mitochondrial matrix
What two molecules come together to make Citrate?
What enzyme catalyzes this reaction?
Oxaloacetate and Acetyl CoA
Citrate synthase
Why do we need to make Citrate in the first step of fatty acit synthesis?
To get Acetyl CoA out of the mitochondria
Once Citrate is in the cytosol, what enzyme breaks it apart into Oxaloacetate and useful Acetyl CoA?
Citrate Lyase
What two molecules positively regulate Citrate Lyase?
Insulin and glucose (High energy state? Upregulate fatty acid synthesis!)
What two molecules negatively regulate (inhibit) Citrate Lyase?
Poly-Unsaturated Fatty Acids (PUFA)
Leptin (Fullness hormone)
What two molecules positively regulate Acetyl-CoA Carboxylase?
Citrate (earlier step pushes forward)
Insulin (Make that fatty acid, get glucose out of the blood!)
What five molecules negatively regulate Acetyl CoA Carboxylase
- Glucagon
- PUFA
- Epinephrine (scare that fat away!)
- Elevated AMP (low energy? Don’t make fat!)
- Palmitate (end product pushes backwards)
Is Acetyl CoA Carboxylase (ACC) more active by itself, or with its friends as a polymer?
ACC’s active form is as a polymer. (visable under the right kind of microscope)
What does Malonyl CoA inhibit?
Carnitine Acyltransferase - the rate limiting step in Fatty Acid degradation
What form is active Fatty Acid Synthase (FAS) found in?
How many enzyme activities does each complex perform?
What other important protien is present?
- A complex of two identical dimers.
- Each of the complexes has 7 enzyme activities
- Acyl Carrier Protien
