Involved in the gluconeogenesis. Catalyzes the conversion of oxaloacetate (OAA) to phosphoenolpyruvate (PEP) through direct phosphoryl transfer between the nucleoside triphosphate and OAA. ATP + oxaloacetate = ADP + CO2 + phosphoenolpyruvate Binds 1 Mn(2+) ion per subunit. Allosterically activated by calcium. It may represent the only case of a monomeric, allosteric enzyme. Carbohydrate biosynthesis; gluconeogenesis. Monomer. Induced upon entry into stationary phase and by cyclic AMP (cAMP). Repressed by glucose (catabolite repression) and by CsrA. Belongs to the phosphoenolpyruvate carboxykinase (ATP) family. Translation N-terminally extended.