Main points about 2,3-BPG regulation of hemoglobin:
* 2,3-BisPhosphoGlycerate (BPG) is produced in erythrocytes (red blood cells) in an offshoot of glycolysis (Rapoport Leubering Cycle or Shunt)
* 2,3-BPG binds to the central channel that is open in the T state (high oxygen affinity) (but not the R state (low oxygen affinity))
* Binding of 2,3-BPG stabilizes the T state, decreasing affinity for oxygen (shifting the curve to the right)
* Fetal hemoglobin has a lower affinity for 2,3-BPG, so it has its affinity decreased less (gets shifted right LESS)
- so it has a higher affinity for oxygen than adult hemoglobin in the presence of 2,3-BPG (left-shifted)
- this lets it efficiently bind and release oxygen in the low-oxygen conditions it’s exposed to
* Production of 2,3-BPG is upregulated (more is made) at high altitudes (where there’s less oxygen available in the lungs) to allow for roughly the same amount of oxygen to be delivered to tissues as if you were at sea level
* Small decrease in oxygen saturation in lungs - pick up a little less
* But big decrease in oxygen saturation in tissues - drop off a lot
* 2,3-BPG is classified as an allosteric, heterotropic, negative modulator
external figures: biocheminfo.com... ; themedicalbioc... ; LHcheM, CC BY-SA 3.0 creativecommon..., via Wikimedia Commons
Longer version: • Regulation of hemoglob...
Much more here: bit.ly/sicklece... & • Biochemistry of Sickle...
More on the Bohr effect: blog form: bit.ly/bohreffect ; RU-vid: • Biochemical basis of t...
More on hemoglobin cooperativity: • Cooperative binding & ...
more about all sorts of things: #365DaysOfScience All (with topics listed) 👉 bit.ly/2OllAB0 or search blog: thebumblingbioc...
29 сен 2024
