16-FA oxidation Flashcards
Fatty acid oxidation is a major source of …
cell ATP (energy)
- oxidation of FA in mitochondria
- where the enzymes of FA oxidation are close to the electron transport chain
- occur at the ß-carbon atom resulting in elimination of 2 terminal carbons as acetyl-CoA leaving fatty acyl CoA.
ß-oxidation pathway
acyl CoA synthetase reaction (activation of FA) occurs in ……………..
the outer mitochondrial membrane (cytoplasm)
carries long-chain activated fatty acids into the mitochondrial matrix
transporter carnitine
ß-oxidation has 4 steps :
1- Dehydrogenation (FAD-dependent)
2- Hydration
3- Dehydrogenation (NAD-dependent)
4- Thiolysis (remove 2C as acetyl CoA) “cleavage”
high level of ATP in the cell, then the rate of ß-oxidation will …………. (feedback inhibition)
Decrease
- precursor of FA synthesis
- inhibts Carnitine Palmitoyl Transferase (no FA enters the mitochondria)
- inhibits ß-oxidation
- produced by the enzyme Acetyl-CoA Carboxylase
Malonyl-CoA
1- ß-oxidation stimulated ——–> ……… Acetyl CoA carboxylase
2- ß-oxidation inhibited———-> ……… Acetyl CoA
1- Inactive
2- Active
an enzyme that plays a key role in regulating fatty acid metabolism
-is inhibited by phosphorylation
acetyl CoA carboxylase (ACC)
degradation occurs because epinephrine and glucagon stimulate lipolysis; increases ß-oxidation
Starvation
insulin inhibits lipolysis; decreases ß-oxidation
Fed state
- requires additional enzymes
- produce less energy than saturated FA
oxidation of unsaturated FA
- occurs in brain tissue in order to oxidize short-chain FAs.
- there is one carbon atom removed from α position
- doesn’t require CoA and doesn’t generate high-energy phosphate
- significant in the metabolism of dietary FAs that are methylated on ß-carbon e.g. peroxisomes
α-oxidation pathway
