Pyruvate to glucose, mostly in the liver
Route: Pyruvate → Oxaloacetate → Phosphoenolpyruvate → 2-Phosphoglycerate → 3-Phosphoglycerate → 1,3-Bisphosphoglycerate → Glyceraldehyde 3-phosphate + Dihydroxyacetone phosphate → Fructose 1,6-bisphosphate → Fructose 6-phosphate → Glucose 6-phosphate → Glucose
Mostly glycolysis run backwards. Seven of its ten steps are reversible and the same enzymes work in both directions. The three irreversible steps are bypassed by different enzymes: pyruvate carboxylase and PEP carboxykinase replace pyruvate kinase, fructose 1,6-bisphosphatase replaces phosphofructokinase-1, and glucose 6-phosphatase replaces hexokinase. Pyruvate carboxylase works in the mitochondrial matrix; the oxaloacetate leaves as malate and is turned back into oxaloacetate in the cytosol. Everything above the aldolase step happens twice per glucose, once for each pyruvate. Making one glucose costs four ATP and two GTP, and two NADH.
Practice this pathway All pathways
| Step | Enzyme | EC | In | Out |
|---|---|---|---|---|
| 1 | Pyruvate carboxylase | 6.4.1.1 | ATP, HCO₃⁻ | ADP, Pᵢ |
| 2 | PEP carboxykinase | 4.1.1.32 | GTP | GDP, CO₂ |
| 3 | Enolase | 4.2.1.11 | H₂O | |
| 4 | Phosphoglycerate mutase | 5.4.2.11 | ||
| 5 | Phosphoglycerate kinase | 2.7.2.3 | ATP | ADP |
| 6 | GAP dehydrogenase | 1.2.1.12 | NADH | NAD⁺, Pᵢ |
| 7 | Aldolase | 4.1.2.13 | ||
| 8 | Fructose 1,6-bisphosphatase | 3.1.3.11 | H₂O | Pᵢ |
| 9 | Phosphoglucose isomerase | 5.3.1.9 | ||
| 10 | Glucose 6-phosphatase | 3.1.3.9 | H₂O | Pᵢ |
Enzyme names and EC numbers are those used on the interactive board. Checked against sources: see the claim table in the repository (tools/pathway_data/checks).