4.2 Pyruvate Oxidation
Extraction of the remaining free energy in the pyruvate molecules from glycolysis (& the citric acid cycle)
DECARBOXYLATION – removal of carboxyl group (COO-)
Released as CO2 (waste)
Turns Pyruvate → acetyl group
1/3rd of CO2 we exhale
Followed by oxidation of the remaining two carbon molecules, producing an acetyl group
DEHYDROGENATION
Transfers 2e and 1p o NAD+ → NADH
Releases H+ into solution (extra)
Acetyl bonds to coenzyme A →ACETYL-COA
2 pyruvate + 2 NAD+ + 2 CoA → acetyl-CoA + 2 NADH + 2 H+ + 2 CO2
Large pores in outer membrane allow pyruvate through
For inner membrane a pyruvate specific membrane carrier is required
Once in the matrix, it converts into an acetyl group
which is then temporarily bonded to a sulfur atom on the end of a large molecule called coenzyme A, or CoA.
The result is an acetyl-CoA complex.
So far...
2 ATP (net)
2 NADH
2 NADH (1 for each pyruvate)
Isnt acetylcoa a yield??
Now, acetyl-CoA enters the citric acid cycle
Extraction of the remaining free energy in the pyruvate molecules from glycolysis (& the citric acid cycle)
DECARBOXYLATION – removal of carboxyl group (COO-)
Released as CO2 (waste)
Turns Pyruvate → acetyl group
1/3rd of CO2 we exhale
Followed by oxidation of the remaining two carbon molecules, producing an acetyl group
DEHYDROGENATION
Transfers 2e and 1p o NAD+ → NADH
Releases H+ into solution (extra)
Acetyl bonds to coenzyme A →ACETYL-COA
2 pyruvate + 2 NAD+ + 2 CoA → acetyl-CoA + 2 NADH + 2 H+ + 2 CO2
Large pores in outer membrane allow pyruvate through
For inner membrane a pyruvate specific membrane carrier is required
Once in the matrix, it converts into an acetyl group
which is then temporarily bonded to a sulfur atom on the end of a large molecule called coenzyme A, or CoA.
The result is an acetyl-CoA complex.
So far...
2 ATP (net)
2 NADH
2 NADH (1 for each pyruvate)
Isnt acetylcoa a yield??
Now, acetyl-CoA enters the citric acid cycle