Gluconeogenesis Flashcards
What is gluconeogenesis?
Synthesis of glucose from other molecules
Why is gluconeogenesis needed?
Glucose is needed for brain and red blood cells
. other cells use FA
Glycogen stores in the liver are limited and muscles cant release glucose into the blood.
What is the first step in gluconeogenesis.
State the equations and where this occurs
In the Mitochondrion
HCO3- + ATP-> HOCO2-P +ADP
Biotin+ HOCO2-P -> Biotin-CO2 +Pi
Biotin-CO2 + Pyruavte -> Biotin + OAA
What are the products from the first step of gluconeogenesis and what transports it to where?
OAA transported by Malate or Asp to cytoplasm
What is the 2nd step in gluconeogenesis.
State the equations and where this occurs
PEP carboxykinase
OAA + GTP -> PEP + GDP +CO2
in Cytoplasm
What is the overall irreversible reaction 1 in Gluconeogenesis?
Pyruvate + CO2 + ATP + GTP -> PEP + CO2 + ADP + GDP
What is the irreversible reaction 2 in gluconeogenesis
Fructose-1,6-bisphosphate + H2O -> F-6P +Pi
F-1,6-bisphosphatase
What is the irreversible reaction 3 in gluconeogenesis?
Where does it occur?
Glucose-6-phosphate +H2O -> Glucose +Pi
w/glucose-6-phosphate
in the endoplasmic reticulum
Why is the enzymes essential for reaction 3?
G-6-P cannot cross the plasma membrane, so tissues w/o enzyme cannot export glucose
Problem- No stores of pyruvate to maintain gluconeogenesis?
What is the bodies solution?
Lactate- Cori Cycle
Glucogenic amino acids
Describe the CORI CYCLE
Lactate-> Pyruvate-> Glucose ( with LDH in the liver)
Glucose->Pyruvate -> Lactate
Describe Glucogenic AA
Alanine is more important
Muscle catabolism releases Ala into the blood
Converted to pyruvate
How does the CORI cycle match up with Alanine?
Pyruvate can make lactate and Alanine
Alanine can make Pyruvate again or produce UREA
