2,3-bisphosphoglyceric acid
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| Surname | 2,3-bisphosphoglyceric acid | |||||||||
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| Molecular formula | C 3 H 8 O 10 P 2 | |||||||||
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| properties | ||||||||||
| Molar mass | 266.04 g mol −1 | |||||||||
| Physical state |
firmly |
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| solubility |
slightly soluble in water: 10.2 g l −1 (20 ° C) |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||
2,3-Biphosphoglyceric acid ( 2,3-BPG ), outdated known as 2,3-diphosphoglycerate ( 2,3-DPG ), is a C 3 body with a charged phosphate group on the 2nd and 3rd carbon atom. It also has a charged carboxy group on the first carbon atom . In total, it is five times negatively charged in solution (blood). It is formed in the Rapoport-Luebering cycle , a byway of glycolysis , from 1,3-biphosphoglyceric acid with the participation of the enzyme bisphosphoglycerate mutase . Under physiological conditions, around 20 percent of the 1,3-biphosphoglyceric acid produced during the glycolysis of the erythrocytes is converted to 2,3-BPG, the remaining 80 percent pass through the main route of glycolysis via 3-phosphoglycerate .
2,3-BPG plays a crucial role in regulating hemoglobin (Hb). If it binds to the tense form of hemoglobin (deoxyhemoglobin), this form is stabilized and cannot change into the R-form with an affinity for oxygen. With bound 2,3-BPG, hemoglobin releases oxygen even at a low partial pressure . 2,3-BPG makes further oxygenation of hemoglobin more difficult and facilitates the release of the oxygen bound to Hb. This moves the equilibrium of the oxygen binding curve (HbO 2 ↔ deoxy-Hb) to the right, i.e. H. moved to the side of deoxy-Hb. It is therefore plausible that more oxygen can be given off with a relatively reduced oxygen uptake. The phenomenon of the oxygen binding curve shifting to the right has practical consequences for mountaineering and diving. In altitude training , this fact is used to first raise the 2,3-BPG value, whereby EPO -mediated increased erythropoiesis is achieved.
In stored blood , 2,3-BPG has to be replaced by an analogue such as glucose or inosine because it is unstable and breaks down quickly. It is constantly being re-synthesized in the body. The gamma globin of fetal hemoglobin (HbF) has a lower affinity for 2,3-BPG. This increases the affinity of fetal hemoglobin for oxygen compared to adult hemoglobin (HbA). This enables easy transfer of oxygen from the mother to the fetus .
The arthropods have hemocyanin as a respiratory pigment . Here the lactate takes over the function of 2,3-BPG and leads to a shift in the middle part of the oxygen binding curve to the right.
Individual evidence
- ↑ Entry on 2,3-Diphosphoglyceric acid in the Human Metabolome Database (HMDB) , accessed on September 24, 2013.
- ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.