piruvátkináz

Piruvátkináz, also known as pyruvate kinase or PK, is an enzyme that catalyzes the final step of glycolysis. In this reaction, it converts phosphoenolpyruvate (PEP) into pyruvate, while also generating adenosine triphosphate (ATP) from adenosine diphosphate (ADP). This ATP production is a crucial part of cellular energy generation. There are several isoforms of pyruvate kinase found in different tissues, each with slightly different properties and regulatory mechanisms. For example, L-type pyruvate kinase is predominantly found in the liver, while M-type pyruvate kinase is found in muscle and other tissues.

The activity of pyruvate kinase is tightly regulated to control the rate of glycolysis according to the cell's energy demands. This regulation can occur through allosteric effectors, such as fructose-1,6-bisphosphate, which activates the enzyme, and ATP and alanine, which inhibit it. This feedback mechanism helps prevent excessive glucose breakdown when energy levels are high. Defects in pyruvate kinase can lead to various health conditions, most notably pyruvate kinase deficiency anemia, a hereditary form of hemolytic anemia. In this condition, red blood cells lack sufficient functional pyruvate kinase, impairing ATP production and leading to premature cell death.