Succinyl CoA Synthetase

STEP 5
Succinyl CoA Synthetase

AKA succinyl thiokinase, this enzyme catalyzes the only substrate-level phosphorylation in the TCA cycle. The overall reaction occurs thru several high-energy intermediates, possibly including succinyl phosphate.
GDP is phophorylated to GTP, which then goes on to phosphorylate ADP - the only ATP produced directly by the TCA cycle.

DG = ~0 kJ/mol

DGº' = -3.3 kJ/mol

K_eq = 3.8

substrate: succinyl-CoA (CO₂CH₂CH₂CO-SCoA)

product: succinate (CO₂CH₂CH₂CO₂)

		Citric Acid Cycle
		Heather Shepheard
		Tainted by Chemical X
		succinyl-CoA synthetase