Ketone Body Synthesis Flashcards
When does Ketone Body Synthesis occur?
When Glycogenolysis / GNS substrates are exhausted (starvation)
What are 3 Ketones produced & utilized in Ketone Body Synthesis?
Beta (0-3-) Hydroxybuturate
Acetoacetate
Acetone
What is the primary Ketone body utilized?
Beta Hydroxybuturate
What is the first Ketone Body produced?
Acetoacetate
Other than sugar, Ketones are the only other substrate that can cross what?
Blood-Brain Barrier
Where are Ketone Bodies used?
Muscle
Brain
Heart
Why is Ketone Body Synthesis utilized as an energy pathway as opposed to other pathways?
Oxaloacetate is depleted from reoccurring GNG cycles.
Approaching a starvation state what will be up-regulated prior to Ketone Body Synthesis?
GNG
Beta-Oxidation
How does Ketone Body Synthesis start?
High concentrations of Acetyl CoA produced from Beta Oxidation provide the substrates to start Ketone Body Synthesis
What is step 1 of Ketone Body Synthesis?
Acetyl CoA + Acetyl CoA convert into AcetylAcetyl CoA
What is the enzyme that converts 2 Acetyle CoA’s into AcetylAcetyl CoA?
AcetylAcetyl CoA Thiolase
What is step 2 of Ketone Body Synthesis?
AcetylAcetyl CoA is converted into HMG CoA
What is an input for step 2 of Ketone Body Synthesis?
A 3rd Acetyl CoA molecule
What is the enzyme that converts AcetylAcetyl CoA into HMG CoA?
HMG-CoA Synthase
What is step 3 of Ketone Body Synthesis?
HMG-CoA is converted into Acetoacetate
What is the enzyme that converts HMG-CoA inot Acetoacetate?
HMG-CoA Lyase
Once Acetoacetate is formed, how many pathways for Ketone Bodies are there?
2 pathways
What is step 4(A) of Ketone Body Synthesis?
Acetoacetate is converted into Acetone
What is a byproduct of step 4(A) of Ketone Body Synthesis?
CO2
What is the enzyme that converts Acetoacetate into Acetone?
Acetoacetate Dehydrogenase
What is step 4(B) of Ketone Body Synthesis?
Acetoacetate is converted into Beta Hydroxybutrate
What is the enzyme that converts Acetoacetate into Beta Hydroxybutrate?
Beta Hydroxybuturate Dydrogenase
4 sources of regulation for Ketone Body Synthesis are?
HSL
Glucagon
Pyruvate Carboxylase
Malate Dehydrogenase
