45bisfosfat

45bisfosfat, also known as 2,3-bisphosphoglycerate (2,3-BPG), is a molecule found in red blood cells. It plays a crucial role in regulating the oxygen-carrying capacity of hemoglobin. Hemoglobin is the protein in red blood cells responsible for transporting oxygen from the lungs to the body's tissues.

The binding of oxygen to hemoglobin is influenced by several factors, including the concentration of 2,3-BPG. When 2,3-BPG binds to a specific site on the hemoglobin molecule, it reduces hemoglobin's affinity for oxygen. This means that hemoglobin is more likely to release oxygen to the surrounding tissues, particularly in areas where oxygen levels are low, such as during intense physical activity or at high altitudes. This effect is known as the Bohr effect, though 2,3-BPG's influence is a distinct, albeit related, mechanism of oxygen delivery.

The production of 2,3-BPG is part of the glycolysis pathway, specifically the Rapoport-Lueber pathway. Conditions that lead to increased oxygen demand, such as chronic hypoxia (low oxygen levels) or anemia, can stimulate the production of 2,3-BPG, thereby enhancing oxygen release to tissues. Conversely, conditions that increase hemoglobin's affinity for oxygen, like alkaline environments, can lead to a decrease in 2,3-BPG levels. Its concentration is therefore a sensitive indicator of the body's metabolic state and oxygen requirements.