Succinyl-CoA ligase, alpha subunit (IPR005810)

Short name: CoA_lig_alpha

Overlapping homologous superfamilies

Family relationships



There are four different enzymes that share a similar catalytic mechanism which involves the phosphorylation by ATP (or GTP) of a specific histidine residue in the active site. These enzymes are

  • ATP citrate-lyase (EC: [PMID: 1371749], the primary enzyme responsible for the synthesis of cytosolic acetyl-CoA in many tissues, catalyzes the formation of acetyl-CoA and oxaloacetate from citrate and CoA with the concomitant hydrolysis of ATP to ADP and phosphate. ATP-citrate lyase is a tetramer of identical subunits.
  • Succinyl-CoA ligase (GDP-forming) (EC: [PMID: 8401211] is a mitochondrial enzyme that catalyzes the substrate level phosphorylation step of the tricarboxylic acid cycle: the formation of succinyl-CoA from succinate with a concomitant hydrolysis of GTP to GDP and phosphate. This enzyme is a dimer composed of an alpha and a beta subunits.
  • Succinyl-CoA ligase (ADP-forming) (EC: [PMID: 3002435] is a bacterial enzyme that during aerobic metabolism functions in the citric acid cycle, coupling the hydrolysis of succinyl-CoA to the synthesis of ATP. It can also function in the other direction for anabolic purposes. This enzyme is a tetramer composed of two alpha and two beta subunits.
  • Malate-CoA ligase (EC: (malyl-CoA synthetase) [PMID: 7961516], is a bacterial enzyme that forms malyl-CoA from malate and CoA with the concomitant hydrolysis of ATP to ADP and phosphate. Malate-CoA ligase is composed of two different subunits.

This entry describes succinyl-CoA synthetase alpha subunits, but does not discriminate between GTP-specific and ATP-specific reactions. ATP citrate lyases appear to form an outgroup, and are not included in this entry.

GO terms

Biological Process

GO:0008152 metabolic process

Molecular Function

GO:0003824 catalytic activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.