Enables phosphoenolpyruvate carboxykinase (GTP) activity. Involved in several processes, including carboxylic acid metabolic process; gluconeogenesis; and positive regulation of insulin secretion. Located in mitochondrion. Orthologous to human PCK2 (phosphoenolpyruvate carboxykinase 2, mitochondrial). [provided by Alliance of Genome Resources, Apr 2022]