Fatty acid oxidation Flashcards
What type of fatty acid cannot enter the mitochondria?
Long chain fatty acid
How do medium and short chain fatty acids enter the mitochondria?
simple diffusion
How are fatty acids actiated in the mitochondria?
transformed into Acyl-CoAs
Carnitine transport system
Transports acyl-CoAs across the inner mitochondria membrane by turning into acylcarnitine (CPT1) then transferring back to carnitine (CPT2)
What does beta-oxidation produce?
1 Acetyl-CoA, 1 FADH2, 1 NADH, an acyl-CoA reduced by 2 carbons
Acyl-CoA DH
Makes FADH2 (1st step beta oxidation)
Enoyl-CoA hydratase
Adds H2O
3HCoADH
makes NADH (3rd step beta oxidation)
beta-ketothiolase
Adds HSCoA to make Acetyl Co-A and acyl-CoA
How many ATP are formed from FADH2?
2
How many ATP are formed from NADH?
3
Very long chain acyl-CoA DH prefers how many carbon?
12 to 24
Long-chain acyl CoA DH prefers how many carbons?
12 to 16
Medium chain Acyl-CoA DH prefers how many carbons?
6 to 8
Short chain acyl-CoA DH prefers how many carbons?
4>6>8
What inhibits CPT 1?
Malonyl-CoA
What happens to beta oxidation when insulin predominates?
Acety-CoA carboxylase is stimulated, Malonyl-CoA concentration increased, so fatty acid synthesis is stimulated while beta-oxidation is inhibited
What happens to beta oxidation when glucaogon predominates?
Acetyl-CoA carboxylase is inhibited, Malonyl-CoA concentrations decrease. Inhibition of CPT 1 is relieved.
What happens to the product of odd-numbered fatty acid beta oxidation?
propionyl-CoA is converted to succinyl-CoA, which can be used in gluconeogenisis
Where does the oxidation of very long chain fatty acids occur?
peroxisomes
What is unquie about the modified oxidation in peroxisomes?
oxidation is not linked to cofactor reduction
Omega oxidation
Occurs in the ER. Utilizes Cytochrome P450. Is the detox rxn in humands. Produces a dicaroxylic acid
What are the 3 ketone bodies?
Acetoacetate, Acetone, beta-hydroxybutyrate
HMG-CoA synthase and lysase
Produce only ketone bodies in the liver mitochondria
What is the only place ketone synthesis enzymes can be found?
only liver mitochondria
What causes the fruity breath in keto-acidosis?
Acetone
Medium chain acyl-CoA deficiency
Most common genetic disease of lipid metabolism. Causes non-ketotic hypoglycemia, fatty infiltration of liver, short chain dicarboxylic acids can be found in the urine
Carnitine deficiency
Insufficient fatty acid delivery to mitochondria. Causes non-ketotic deficiency. Can treat with oral carnitine
CPT I deficiency
LCFA can go into the mitochondria. Hepatomegaly with fatty infiltration. Causes increased plasma carnitine levels. Can be overcome with MCFA
Refsum disease
Deficiency in a component of branched-chain oxidation. Serious neurological deficiency. Reduce phytanic acid in diet.
