Gluconeogenesis Flashcards
Where does gluconeogenesis occur?
- Liver (90%)
- Kidney (10%)
in both mitochondria and cytosol
What reactions in the body that occur in both cytosol and mitochondria
- Heme synthesis
- Urea cycle
- Gluconeogenesis
What are the substrates used for gluconeogenesis?
- TCA intermediates (malate)
- Lactate
- Glycerol and propionylCoA
- Gluconeogenic amino acids
What are examples of your gluconeogenic amino acids?
- Arginine (R)
- Histidine (H)
- Methionine (M)
- Valine (V)
- Alanine (A)
- Asparagine (
- Aspartate (D)
- Cysteine (C)
- Glutamate (E)
- Glycine
- Proline (P)
- Serine (S)
What is the rate limiting step in gluconeogenesis?
F1,6BP to F6P
via Fructose 1,6 bisphosphatase
what is the first step of gluconeogenesis?
Pyruvate to oxaloacetate
via: pyruvate carboxylase
What are the steps involved to convert pyruvate to Phosphoenolpyruvate
- Pyruvate to oxaloacetate via pyruvate carboxylase
2. Oxaloacetate to phosphoenolpyruvate via PEP carboxykinase
What enzyme is used to convert F1,6BP to F6P?
F1,6 BP
What enzyme is used to convert G6P to glucose?
G6 phosphatase
What are the coenzymes needed by pyruvate carboxylase?
- Biotin
2. ATP
In order to transport oxaloacetate out of the mitochondrion, it is reduced to?
malate
What enzymes require biotin as cofactor?
- Pyruvate carboxylase (pyruvate to oxaloacetate)
- Acetyl CoA carboxylase (acetyl CoA to malonyl CoA)
- Propionyl CoA carboxylase (Propionyl CoA to methylmalonyl CoA
What step in gluconeogenesis requires GTP?
Oxaloacetate to phosphoenolpyruvate
via phosphoenolpyruvate carboxykinase
What is the key enzyme that catalyzes the net transfer out of the citric acid cycle into gluconeogenesis?
Phosphoenolpyruvate carboxykinase
What is the rate limiting step of gluconeogenesis?
F1,6BP to F6P via fructose 1,6 bisphosphatase
What inhibits the conversion of F1,6BP to F6P?
- Fructose 2,6 bisphosphate
What step in gluconeogenesis is shared with glycogenolysis?
G6P to Glucose via glucose 6 phosphatase
___ cycle is the formation of glucose from lactate
Cori Cycle
What regulates gluconeogenesis?
- Glucagon
- Availability of gluconeogenic substrates
- Allosteric activation of hepatic pyruvate carboxylase by acetyl CoA
- Allosteric inhibition of F1,6BP by AMP
What are the energy requirements of gluconeogenesis if from pyruvate?
- Cleavage of 6 high-energy phosphate
2. Oxidation of 2 NADH
The energy requirements of gluconeogenesis is derived from?
Oxidation of fatty acids
[Clinical Correlates]
Glucosuria happens when the venous blood glucose concentration is
10.0 mmol/L (renal threshold)
