Fatty Acid Catabolism (L7) Flashcards
How do you beta-oxidize a mono-unsaturated acid?
Use enoyl-CoA isomerase when you get to the cis double bond to make it trans, and continue with beta-oxidation with Enoylhydratase.
How do you beta-oxidize a poly-unsaturated acid?
use enoyl-CoA isomerase for the 1st cis-double bond, and then if you get a cis, followed by a trans double bond, then use 2,4-dienoyl-CoA reductase, and then continue with enoyl-CoA isomerase
Refsum’s disease is a cause of:
deficiencies in alpha-oxidation.
Alpha-ox happens significantly in peroxisomes.
Refsum’s is an autosomal recessive disease
What are the main enzymes affected by ATP/ADP ratios?
ox-phos, ETC
Phosphofructokinase, pyruvate kinase, citrate synthase, isocitrate DH, amino acid degradation (ie glutamate DH)
Also G6P inhibits hexokinase
What is the difference b/w ACC1 and ACC2?
Acetyl-CoA Carboxylase:
1: highly expressed in liver and adipose, involved in FA SYNTHESIS
2: Highly expressed in liver, skeletal m., and heart, regulates FA oxidation by forming malonyl-CoA to inhibit carnitine acyltransferase I
What is the longest FA that can be made from FA synthase?
Palmitate (aka palmitic acid) C16:0
How is it ensured that Glucose-6-phosphate generation in the liver occurs only when blood glucose levels are high?
In skeletal m. hexokinase is allosterically inhibited by G6P. With a high concerntration of blood glc, the glc that is not phosphorylated by hexokinase will leave the skeletal m., and travel to the liver, where it becomes G6P via glucokinase which cannot be allosterically inhibited by G6P.
Glucokinase has a low affinity for Glc, so it only makes G6P when [Glc] is high.
Why can’t glycerol be used for triglyceride synthesis in adipose tissue?
To make triacylglycerol, FA-CoA is needed with Glycerol-3-P. However Glycerol can only be used in the liver to make Glycerol-3-P b/c Glycerol Kinase is present in the liver only. In the liver and adipose tissue though, Glycerol-3-P DH is present in the cytosol to make Glycerol-3-P from DHAP.
