Involved in gluconeogenesis. Catalyzes the conversion of oxaloacetate (OAA) to phosphoenolpyruvate (PEP) through direct phosphoryl transfer between the nucleoside triphosphate and OAA (By similarity). ATP + oxaloacetate = ADP + CO2 + phosphoenolpyruvate Binds 1 Mn(2+) ion per subunit. Carbohydrate biosynthesis; gluconeogenesis. Monomer. Belongs to the phosphoenolpyruvate carboxykinase (ATP) family.