Fatty Acid Oxidation Flashcards
What conformation are double bonds usually found?
Cis
When is oxidation of fats particularly important?
- fasting/starving
- ensurance exercise
- neonatal fuel metabolism
What is the main storage form of fatty acids?
Triacylglycerol
How to free fatty acids bind to albumin?
Albumin has hydrophobic patches on the surface which allows fatty acids can be solublised
When is acetyl Co-A produced?
- Protein oxidation
- Carbohydrate oxidation
- Alcohol oxidation
- Fat oxidation
When is acetyl CoA used?
- ketone body synthesis
- oxidation in the citric acid cycle
- Steroid synthesis
- Fat synthesis
Where is acetyl Co-A produced?
The mitochondria
How are fatty acids transported into the mitochondria?
The carnitine shuttle
What reaction occurs to help trap fatty acids into the cell?
Fatty acid + ATP + CoA → Acyl-CoA + AMP + pyrophosphate
Which enzymes are involved in the carnitine shuttle?
- Translocase
- Carnitine palmitoyltransferase (CPT)
What direction does carnitine move relative to acyl carnitine in the carnitine shuttle?
Carnitine moves in the opposite direction to acyl carnitine
The carnitine shuttle is specific to fatty acids which are how many carbons long?
18-24
Outline the steps in β-oxidation
- Acyl CoA dehydrogenase inserts a double bond between the alpha and beta carbon
- H2O is added across C=C
- Then the reduced beta carbon is converted to a ketone group
- Finally CoA is added onto the beta carbon
Why poison inhibits dehydrogenases in β-oxidation?
Hypoglycin
What is the overall reaction of the β-oxidation of palmitoyl-CoA
palmitoyl-CoA + 7NAD+ + 7FAD + 7CoASH + 7H2O
↓
8 acetyl Co-A + 7NADH + 7FADH2 + 7H+
Why can’t very long chain fatty acids undergo β-oxidation?
They cannot get into the mitochondria as they are not a substrate of the carnitine shuttle
Where does oxidation of very long chain fatty acids occur?
Peroxisomes
What is a problem associated with build up in VLCFAs?
Neurological damage
What is needed to oxidise unsaturated fatty acids?
Additional enzyme
What is generated in oxidation of odd-chain fatty acids?
propionyl-CoA
What is propionyl-CoA converted to so it can enter the citric acid cycle?
Succinyl-CoA
What enzyme controls lipolysis of triacylglycerol?
Hormone-sensitive lipase
Which chemical primarily determines the fate of fatty acids in cells?
Malonyl-CoA
What is the effect of malonyl Co-A on the carnitine shuttle?
It inhibits the carnitine cycle
