Pyruvate to PEP via OA

Question 1

Strategy of pyruvate to PEP

Answer 1

use ATP to convert pyruvate to a high energy intermediate.

H.E.I = OA

Will then Phosphorylate HEI to make PEP, and lose CO2

Question 2

How is the strategy of Pyr to PEP implemented

Answer 2

1st step requires ATP and 2nd requires GTP.

Why not use only ATP?
GTP is a measure of mitochondrial energy state… GTP present in mito is present in a way that can be measured… ATP always being made and used… cant measure as well

Question 3

Step 1 logic

Answer 3

Decarboxylation of OA which will provide your free energy ∆G for PEP synthesis because b-keto acids are high energy compounds..

Why is this a high E compound?
Large ∆G for the decarboxy rxn, which is the loss of the carbon dioxide, this has a high energy drop, which makes it a high energy compound.

Question 4

Logic for step 2

Answer 4

GTP use connects to the citric acid cycle TCA running, because rxn 5 in TCA produced GTP in kidney and liver.
This is done the in the kidney and liver (major GNG tissues).

Must be coupled for it to be working in our favor

Question 5

First rxn

Answer 5

catalyzed by Pyruvate carboxylase (PC; 1154 AA; homotetrameric)

Question 6

second rxn

Answer 6

catalyzed by phosphoenolpyruvate carboxykinase (PEPCK; 630 AA; monomeric)