Pyruvate carboxylase is an enzyme found in the mitochondria of cells. It plays a crucial role in metabolism by converting pyruvate, a product of glucose breakdown, into oxaloacetate. This reaction is essential for gluconeogenesis, the process of producing glucose from non-carbohydrate sources, and for the citric acid cycle, which generates energy. The enzyme requires biotin as a cofactor and is activated by acetyl-CoA. Its activity helps maintain proper energy levels and supports various metabolic pathways. Dysregulation of pyruvate carboxylase can lead to metabolic disorders, highlighting its importance in cellular function.