Oxidation of Amino acids and fatty acids Flashcards
(31 cards)
What are Fatty acids an important source of?
energy in many organisms and tissues
What is produced during the oxidation of Fatty acids? What can this be used for?
Acetyl-Coenzyme A
-can be used to generate energy via various pathways
What is the mechanism of the conversion of Fatty Acids to Acetyl CoA?
B-oxidation
What does the binding of glucagon to a receptor due to low levels of glucose do?
-causes free FAs to leave the adipocyte, travelling through the blood to provide energy to cells
Where does 95% of biologically available energy of triglycerides reside?
Fatty Acids
Once released by_____, the glycerol is processed via_____
lipase, glycolysis
What can be used to synthesise membrane lipids?
What can also occur?
Fatty acyl coA esters
-also transported into the mitochondrion and oxidised to produce ATP.
What is the first stage of Fatty Acid Oxidation?
Long-chain fatty acids oxidised to give Acetyl-CoA (B oxidation)
What is the second stage of Fatty Acid Oxidation?
Acetyl groups oxidised to C02 via citric acid cycle
What is Stage 3?
Electrons from stages 1 and 2 pass to 02 via respiratory chain, generating ATP
How many steps are there in B-oxidation?
4
What happens for each fatty acid?
these are repeated until the final reaction leaves acetyl-CoA (when starting with an even number of Carbons)
When are additional enzyme steps required?
if the fatty acid is:
-unsaturated
-has an odd number of carbons
What can have series consequences given that stored triacylglycerols are the chief source of energy?
inability to oxidise fatty acids
What is the most common genetic defect?
in US and Northern Europe
-mutation in the gene encoding medium-chain acyl-CoA dehydrogenase (MCAD)
What are the consequences of this?
mortality from the disease is 25-60%
What can be done to counter if recognised early?
infants can be fed low-fat, high carbohydrate diet
What does B-oxidation essentially do?
uses 4 reactions to remove each Acetyl-CoA
What do stages 2 and 3 involve?
citric acid cycle and respiratory chain–> significant amounts of ATP generated
How many additional enzymes are required if an odd number of FAs are present?
3 additional enzymes
What does Oxidative degeneration of amino acids generate?
significant amounts of metabolic energy
What are the 3 circumstances in which amino acid oxidation occurs?
-normal synthesis and degradation of cellular proteins
-when ingested amino acids exceed the needs for protein synthesis
-during starvation when carbohydrates unavailable or uncontrolled diabetes
What is an important feature of amino acid degradation?
to separate the a-amino group from the carbon skeleton
Where are amino acids catabolised?
in vertebrate liver
