Fermentative Glucose Metabolism
Enzymes exclusive to Glycolysis Enzymes Shared between the two pathways Enzymes exclusive to gluconeogenesis
Follow the links on the enzyme name to learn more about its chemistry and its catalytic mechanism. There are also some rationales about how the pathways fit together, which reactions are the same and which must be different to maintain favorable standard free energies for both overall pathways
Glycolysis
Pathway

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Gluconeogenesis
Pathway

 


Glucose

.

ATP
Hexokinase
ADP
↓        ↑ Pi
Glucose-6-Phosphatase
.
Glucose-6-Phosphate

.

Phosphoglucose Isomerase .
.
Fructose-6-Phosphate

.

ATP
Phosphofructokinase
ADP
↓        ↑ Pi
Fructose-1,6-Bisphosphatase
.
Fructose-1,6-Bisphophate

.

Fructose 1,6 bisphosphate aldolase .
 


DiHydroxyAcetone Phosphate


AND

Glyceraldehyde-3-Phosphate

 
Triose Phosphate Isomerase 

 

 

NAD+ + Pi
Glyceraldehyde-3-Phosphate Dehydrogenase
NADH ←
.
.
1,3BisphosphoGlycerate

.

ADP
Phosphoglycerate Kinase
ATP ←
.
.
3 PhosphoGlycerate

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Phosphoglycerate Mutase .
.
2-PhosphoGlycerate

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enolase .
. .
PhosphoEnolPyruvate

.

..

.

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CO2 + GDP (ADP equivalent)
PEP carboxykinase
GTP (ATP equivalent)
Compare the glycolysis, uncatalyzed and gluconeogenesis reactions side by side ADP
Pyruvate Kinase
ATP ←
oxaloacetate
4 Carbon compound
. . . ADP + Pi
pyruvate carboxylase
CO2 + ATP
.

.

---glycolysis "officially" ends here, but 1 of the 3 step below are required!--------------------------------------------------------------------------------------------------
pyruvate decarboxylase
Ethanol fermentation: Beers, Wines The CO2 released is used to raise bread
. lactate dehydrogenase
Lactate fermentation:(overworked muscle cells, red blood cells, yogurt making (Lactobacillus acidophilus))
.

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pyruvate dehydrogenase
This is NOT used in fermentative processes! This takes place in mitochondria and MUST lead to oxidative glucose metabolism.

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Notes: