Succinyl coenzyme A synthetase

Succinyl coenzyme A synthetase (succinate thiokinase) catalyzes the formation of succinate and coenzyme-A, a 4-carbon metabolite, from succinyl-CoA.

Reaction
Succinyl-CoA synthetase catalyzes a reversible step in the citric acid cycle, which involves the substrate-level phosphorylation of GDP.

Isoforms
Johnson et al. describe two isoforms of Succinyl-CoA synthetase in mammals, one which specifically uses ATP for synthesis, and one which utilizes GTP.


 * - ADP-forming -
 * - GDP-forming - ,

The GTP form is the one more commonly used in the human citric acid cycle.

Structure
The crystal structure of Succinyl-CoA synthetase alpha subunit (ATP-binding isoform) was determined by Joyce et al. to a resolution of 2.10 A, with PDB code 1CQJ. .