püruvaatkarboksülaasi

Purüvaatkarboksülaas, also known as pyruvate carboxylase (PC), is a mitochondrial enzyme that catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate. This reaction is a crucial anaplerotic step, meaning it replenishes intermediates in the citric acid cycle, which is essential for cellular energy production and biosynthesis. In mammals, PC is encoded by the PC gene and exists as a homotetramer.

The enzyme plays a vital role in several metabolic pathways. In gluconeogenesis, it provides the oxaloacetate needed for glucose synthesis in the liver and kidneys. In amino acid metabolism, it is involved in the catabolism of certain amino acids, converting their pyruvate derivatives into oxaloacetate for entry into the citric acid cycle. PC is also important for fatty acid synthesis, as oxaloacetate can be transported to the cytoplasm and converted to citrate, a precursor for acetyl-CoA.

Human deficiency in purüvaatkarboksülaasi leads to a group of rare genetic disorders known as pyruvate carboxylase deficiency. These conditions are characterized by severe neurological impairment, developmental delay, and metabolic acidosis. There are different forms of the deficiency, with varying severity and inheritance patterns. Treatment is primarily supportive and focuses on managing symptoms and metabolic imbalances.