STEP
1
Citrate
Synthase
Acetyl-CoA enters the cycle either from Step 0 or
from b-oxidation of fatty acids. The thioester bond between acetate
and CoA is unstable, allowing oxaloacetate (4 carbons) to displace CoA
in a nucleophilic attack on the carbonyl carbon of acetate (2 carbons)
to produce citrate (6 carbons).
CoA returns to step 0 to take another pyruvate,
and oxaloacetate is regenerated in step 8.
| DG |
= -53.9 kJ/mol |
| DGº' |
= -31.4 kJ/mol |
| Keq |
= 3.2 ·10-5 |
