Catalyzes the conversion of oxaloacetate (OAA) to phosphoenolpyruvate (PEP), the rate-limiting step in the metabolic pathway that produces glucose from lactate and other precursors derived from the citric acid cycle. Defects in PCK1 are the cause of cytosolic phosphoenolpyruvate carboxykinase deficiency (C-PEPCKD). A metabolic disorder resulting from impaired gluconeogenesis. It is a rare disease with less than 10 cases reported in the literature. Clinical characteristics include hypotonia, hepatomegaly, failure to thrive, lactic acidosis and hypoglycemia. Autoposy reveals fatty infiltration of both the liver and kidneys. The disorder is transmitted as an autosomal recessive trait. Belongs to the phosphoenolpyruvate carboxykinase [GTP] family. Note: This description may include information from UniProtKB.