Mitochndrial SCS (succinyl-CoA ligase) catalyzes the reaction of succinyl-CoA, ADP, and orthophosphate to form succinate, ATP, and CoA-SH. The rice enzyme has not been experimentally characterized but is inferred to be a heterodimer by orthology to well-studied tomato proteins (Studart-Guimaraes et al. 2005).