fosfofruktokinazë1

Phosphofructokinase-1, often abbreviated as PFK-1, is a crucial enzyme found in the glycolytic pathway. Its primary function is to catalyze the irreversible phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate. This reaction is a key regulatory step in glycolysis, the process by which glucose is broken down to produce energy in the form of ATP.

The activity of PFK-1 is tightly controlled by various allosteric effectors. Adenosine triphosphate (ATP) is a potent inhibitor of PFK-1. When cellular ATP levels are high, it signals that the cell has sufficient energy, and PFK-1 activity is reduced, slowing down glycolysis. Conversely, adenosine monophosphate (AMP) and fructose-2,6-bisphosphate are strong activators of PFK-1. High levels of AMP indicate low energy status, stimulating glycolysis. Fructose-2,6-bisphosphate is a particularly powerful activator and plays a significant role in coordinating glycolysis with gluconeogenesis.

PFK-1 exists in different isoforms, which can vary in their kinetic properties and regulatory mechanisms. These isoforms are often tissue-specific, allowing for differential regulation of glycolysis in various cell types. For instance, the muscle isoform is highly sensitive to AMP, reflecting the high energy demands of muscle tissue.

Deficiencies in PFK-1 can lead to metabolic disorders. Glycogen storage disease type VII, also known as Tarui's disease, is caused by mutations in the PFK-1 gene. This deficiency impairs glycolysis, leading to muscle weakness, pain, and exercise intolerance, as well as hemolytic anemia due to insufficient ATP production in red blood cells.