Lipid metabolism Flashcards
Lipolysis definition?
Breakdown of triglycerides in adipose tissue and fatty acids
What enzymes catalyses lipolysis?
Hormone sensitive lipase
What activates hormone sensitive lipase?
Phosphorylation from glucagon and adrenaline
What inhibits hormone sensitive lipase?
Dephosphorylation from insulin
When does lipolysis take place?
a) fed state
b) fasted state
Fasted state when glucagon is high
What is the fate of glycerol after lipolysis?
Transported from the adipose tissue to the liver.
Converted to glycerol-p using ATP and glycerol kinase
Dihydroxyacetone-p using NAD+. To glyceraldehyde-3p to glucose through gluconeogenesis
What is the fate of fatty acids after lipolysis?
Activation by fatty acyl CoA synthase to form fatty acyl CoA. using ATP
Fatty acyl CoA then undergoes beta-oxidation
Where does activation of fatty acid occur?
Cytosol
Where does beta-oxidation of fatty acyl CoA occur?
Mitochondrial matrix
How does fatty acyl CoA get transported to the mitochondrial matrix
CAT shuttle
Carnitine to acyl carnitine through the addition of acyl
Using CATI
Acyl carnitine into the mitochondrial matrix.
Converted to carnitine using CATII and fatty acyl CoA is reformed.
What is the function of the CAT shuttle?
Move fatty acyl CoA from cytosol (where activation occurs) to mitochondrial matrix (where oxidation occurs)
What is beta oxidation?
The sequential removal of 2 carbon units
What are the steps of beta oxidation?
Oxidation
Hydration
Oxidation
Thiolysis
What does each round of beta oxidation yield?
Acetyl CoA, NADH, FADH2
What is the fate of acetyl CoA formed from beta oxidation when oxaloacetate is high?
TCA cycle
