2Hemoglobin Physiology Flashcards
What happens at BPG=0?
Hemoglobin will have a hyperbolic curve and become completely saturated with oxygen. It binds oxygen in a low oxygen concentration.
Like myoglobin.
What is BPG?
2.3- Bisphosphoglycerate
It affects the hemoglobin binding curve.
It has a Carboxylic acid group, alcohol group that is esterified to phosphate group.
5 - charges on this molecule.
Binds tightly to hemoglobin molecule and alternate it’s oxygen binding characteristics.
Causes a decrease in oxygen affinity of hemoglobin
What happens at BPG=5?
It will take on a sigmoidal curve.
At 4 kPa the hemoglobin holds halo saturation of oxygen. Need to go much higher concentration for hemoglobin to saturate.
What if there was no BPG?
The hemoglobin would not let go of the oxygen.
With some BPG available?
At low oxygen pressure found in the capillaries going to the tissue, hemoglobin releases oxygen because the oxygen binding affinity is lower with the presence of BPG.
At higher elevation, the hemoglobin….
Hemoglobin is not as efficient at picking up oxygen.
What is the job of hemoglobin?
Hemoglobin is in charge of picking up oxygen from the lungs and caring that oxygen to the tissues.
How does BPG cause the effect of making hemoglobin release oxygen?
It binds the positive amino acids, and at the pocket of the hemoglobin where the four tetramers come together. Pocket will find terminal amines on the amino acids, as well as side groups that are contained of lysines in histidines.
Histamines are + in hemoglobin and it is used to binding to the - BPG because histidine is + charge.
What is the charge on BPG at physiological pH?
-5
What is the Bohr effect?
The oxygen binding on hemoglobin changes as a function of pH. The higher the pH then the more oxygen binding, the lower the pH the lower the oxygen is binding.
At pH 7.2, why is there a less binding affinity?
At pH 7.2 there are more His-H+ binding. This causes a more positive charge which binds to the negative BPG. This causes the hemoglobin to have a decrease in oxygen affinity.
Histidine will be + charge and stabilize in the T star and decrease O affinity.
The pH at 7.6…
The lungs are slightly more basic. This causes a decrease in binding of BPG and increase O affinity.
This makes it more basic and CO2 leaves, where it exhales.
The oxygen binding curve does what with pH…..
As the pH increases then the oxygen binding curve increases.
What does CO2 do in the blood?
CO2 from tissue will bind to Hemoglobin in blood. This CO2 will bind with amino terminal residues in the hemoglobin to form carbamino terminal residue.
This reaction releases +, tissue becomes more acidic, decrease O binging, carbamino hemoglobin decrease O binding.
Carbamino residue found mainly in deoxy hemoglobin.
Where do you find carbamino terminal residue primarily?
Deoxy hemoglobin
