The old nomenclature for 2,3-DPG has been updated to 2,3-BPG, which stands for 2,3-bisphosphoglycerate. This small molecule is found in red blood cells at around 5 mmol/L concentrations.
Why it was done:
To align with modern chemical nomenclature standards set by the International Union of Pure and Applied Chemistry (IUPAC).
In 2,3-bisphosphoglycerate (2,3-BPG), the two phosphate groups are attached to two different carbon atoms in the glycerate backbone—the 2nd and 3rd carbons.
Therefore, the term “bisphosphate” is appropriate, as it clarifies that both phosphate groups are not linked to the same atom, which the word “diphosphate” might imply.
What it does:
2,3-BPG stabilizes haemoglobin and facilitates the release of oxygen in tissues. It achieves this by binding to the haemoglobin tetramer and altering its shape, which shifts the oxygen dissociation curve to the right.
As a result, haemoglobin has a lower affinity for oxygen, allowing it to release oxygen more readily in the tissues.
How it’s produced :
It is produced in red blood cells (erythrocytes) through the Luebering-Rapoport pathway, a step in glycolysis. The enzyme 2,3-bisphosphoglycerate mutase (BPGM) converts 1,3-bisphosphoglycerate into 2,3-BPG.
The BPGM gene is located on chromosome 7.
Deficiency:
A deficiency of 2,3-BPG can cause a left-shifted oxygen dissociation curve, which decreases oxygen delivery to tissues. This condition can be caused by alkalosis, low metabolic demand, or, rarely, mutations of the BPGM gene on chromosome 7.
Clinical importance:
Stored blood reduces 2,3-BPG levels, which decreases oxygen delivery to tissues. However, transfused RBCs regenerate 2,3-BPG to normal levels within 12 to 24 hours after transfusion, making this effect clinically insignificant.
Clinical Pearl:
Transfusing blood at least 24 hours before surgery in anaemic patients ensures that the 2,3 BPG level remains normal.
