Metabolic pathway
Ketogenesis
Turns the liver's excess acetyl-CoA into ketone bodies, small soluble molecules that travel through the blood. It is how fat reaches the brain, which cannot burn fatty acids.
- In
- 2 Acetyl-CoA + Water + NADH + Proton
- Out
- 2 Coenzyme A + D-3-Hydroxybutyrate + NAD⁺
- Location
- Mitochondrial matrix
Fun facts
- HMG-CoA synthaseThe same molecule, made in the cytosol by another isoenzyme, is the starting point of cholesterol. Its fate depends on which side of the mitochondrial membrane it is made.
- β-hydroxybutyrate dehydrogenaseThe brain cannot burn fatty acids, but it can burn ketone bodies. After several days of fasting they cover most of its needs, and that is why the body does not have to break down so much muscle to make glucose.
Reactions
| # | Enzyme | ΔG°′ |
|---|---|---|
| 1 | ThiolaseEC 2.3.1.92 Acetyl-CoA ⇌ Acetoacetyl-CoA + Coenzyme A | — |
| 2 | HMG-CoA synthaseEC 2.3.3.10 · irreversibleAcetoacetyl-CoA + Acetyl-CoA + Water → HMG-CoA + Coenzyme A | — |
| 3 | HMG-CoA lyaseEC 4.1.3.4 · irreversibleHMG-CoA → Acetoacetate + Acetyl-CoA | — |
| 4 | β-hydroxybutyrate dehydrogenaseEC 1.1.1.30Acetoacetate + NADH + Proton ⇌ D-3-Hydroxybutyrate + NAD⁺ | — |
0 of 4 reactions with a documented ΔG.
Use Shift to select several
The data sheet includes the map. The logo goes at the bottom.
Sources
- Nelson, D. L. & Cox, M. M. (2021). Lehninger. Principios de bioquímica, 8.ª ed., ch. 17