Succinyl-CoA synthetase functions in the citric acid cycle (TCA), coupling the hydrolysis of succinyl-CoA to the synthesis of either ATP or GTP and thus represents the only step of substrate-level phosphorylation in the TCA (PubMed:34492704, PubMed:40108300). The alpha subunit of the enzyme binds the substrates coenzyme A and phosphate, while succinate binding and specificity for either ATP or GTP is provided by different beta subunits (By similarity). Also able to act as an itaconyl- and malyl-CoA synthetase (PubMed:40108300). {ECO:0000255|HAMAP-Rule:MF_03222, ECO:0000269|PubMed:34492704, ECO:0000269|PubMed:40108300}. This is the function of Ensembl gene identifier ENSG00000163541 (SUCLG1, succinate-CoA ligase GDP/ADP-forming subunit alpha).