Pyruvate Oxidation
During pyruvate oxidation, two pyruvate molecules are transported through the mitochondrial membrane into the matrix and acetyl-CoA is formed.
- The carboxyl group is removed as CO2 via a decarboxylation reaction by the enzyme pyruvate decarboxylase.
- The remaining two-carbon portion is oxidized by NAD+ and forms an acetyl group. During this redox reaction pyruvate is oxidized, NAD+ is reduced.
- Coenzyme A attaches to the acetyl and forms acetyl-CoA. The C-S bond that attaches the CoA to the acetyl group is unstable: it has high potential energy. This prepares the acetyl for further oxidation. Acetyl-CoA is a multifunction compound – most lipids, carbohydrates and proteins are converted into acetyl-CoA. However, if the body needs energy it will be sent into the Krebs cycle; and if it doesn't, it is stored as fat.
Products of Pyruvate Oxidation
2 pyruvate + 2 NAD+ + 2 CoA --> 2 acetyl-CoA + 2 NADH + 2 H+ + 2 CO2
2 Acetyl-CoA are produced and enter the Krebs cycle.
2 NADH are produced and go to the electron transport chain and eventually produce ATP.
2 CO2 are produced and diffuse out of the mitochondria and out of the cell as waste.
2 H+ remain dissolved in the matrix of the mitochondria.
The next stage of the process is The Krebs Cycle.
2 pyruvate + 2 NAD+ + 2 CoA --> 2 acetyl-CoA + 2 NADH + 2 H+ + 2 CO2
2 Acetyl-CoA are produced and enter the Krebs cycle.
2 NADH are produced and go to the electron transport chain and eventually produce ATP.
2 CO2 are produced and diffuse out of the mitochondria and out of the cell as waste.
2 H+ remain dissolved in the matrix of the mitochondria.
The next stage of the process is The Krebs Cycle.