What is PEP Glycolysis

A glucose molecule is split into two pyruvates (pyruvic acid) in ten steps:

1. Phosphorylation: The glucose molecule has an additional phosphate group attached (costs 1 ATP). The result is glucose-6-phosphate.
2. Isomerization: The enzyme phosphohexose isomerase converts the glucose-6-phosphate to fructose-6-phosphate (no ATP consumption!).
3. Phosphorylation 2: The enzyme phosphofructokinase phosphorylates fructose-6-phosphate to fructose-1,6-bisphosphate while consuming ATP (costs 1 ATP).
4. Splitting: The enzyme aldolase splits fructose-1,6-bisphosphate into dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP).
5. DHAP conversion: Another enzyme converts DHAP to GAP, which means that two identical glyceraldehyde-3-phosphate (GAP) are now available. From now on, all reactions run twice.
6. CAP conversion: The enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the conversion of GAP to 1,3-bisphosphoglycerate (1,3BPG). At the same time, there is a reduction in NAD + to NADH.
7. ATP win: The 1,3-bisphosphoglycerate is now converted to 3-phosphoglycerate by the enzyme phosphoglycerate kinase (PGK). The enzyme causes the phosphate group to be transferred to ADP, creating an ATP. Since the reaction takes place on two molecules, there are also 2 ATP).
8. Rearrangement: The enzyme phosphoglycerate mutase (PGM) converts 3-phosphoglycerate to 2-phosphoglycerate.
9. Creation of PEP: 2-phosphoglycerate is converted to phosphoenolpyruvate (PEP) by the enzyme enolase.
10. ATP win: The enzyme pyruvate kinase catalyzes the final reaction of PEP to pyruvate. The phosphate group is transferred from the enzyme to ADP, which again creates ATP (another 2 ATP).