Week 5: Fatty Acid Oxidation Flashcards
When does FA oxidation occur?
Fasting state
Fatty Acid oxidation transport
FA-albumin carries in the blood and FATP transports into the cells
FA + CoA -FA-CoA synthetase-> Fa+CoA (trapping in the cell)
FA-CoA binds to a FABP to protect hydrophobicity and transport to the mitochondria for β-oxidation
Where are fatty acids oxidized?
Mitochondria
Describe transport of FA-CoA + FABP to its destination
Carnitine Palmitoyl Transferase
CPT-1 is located on the outer mitochondrial membrane and converts the FA-CoA complex into FAcyl-carnitine
FA-carnitine can now be transported into the mitochondria by Carnitine Acyl-carnitine translocase which is a 1-1 antiporter
CPT2 takes Facyl-Carnitine and converts it back to FA-CoA releasing carnitine
Carnitine is exported back out into the intermembrane space by Carnitine Acyl-carnitine translocase to allow carnitine to bring in another FA-CoA
What is CPT-1?
- Carnitine Palmitoyl Transferase
- CPT-1 is located on the outer mitochondrial membrane and converts the FA-CoA complex into FAcyl-carnitine
FA oxidation
occurs on the beta carbon releasing acetyl CoAs which can enter the TCA cycle
What is the most common FA we have?
C16:0 palmitate
C16:0 palmitate rounds of β oxidation
7x FA oxidation
8 Acetyl CoAs
The difference in reactions of β oxidation in skeletal muscle and liver
They are the same except that β oxidation in skeletal muscle is only used to generate ATP
In the liver, we need to prevent a futile loop
Fed state in liver
glycogen stores are full then we go to FA synthesis
The last step of the FA synthase complex is to attach a CoA to form FA-CoA
So this would become a futile loop in the fed state in the liver
Acetyl CoA in the cytoplasm is generated from citrate by Citrate lyase into OAA and Acetyl CoA
Acetyl CoA is converted into malonyl CoA by acetyl CoA Carboxylase
Malonyl CoA + Acetyl CoA -> FA-CoA
However, in the liver [malonyl CoA] inhibits CPT1 to prevent a futile loop
