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Flashcards in 2Hemoglobin Physiology Deck (24):

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=0?

Hemoglobin will have a hyperbolic curve and become completely saturated with oxygen. It binds oxygen in a low oxygen concentration.

Like myoglobin.


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?



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


What is HbF?

Expressed when we are fetus and is increase oxygen binding hemoglobin and doesn't bind BPG as tightly as HbA will take Oxygen from mothers hemoglobin. Fetus has increase Oxygen affinity than the mother and necessary for survival. This decreases efficiency to deliver O to tissues but is necessary.


What is HbA2?

Naturally occurring at small amount. This allows an increase of oxygen that hemoglobin can grab in lungs particularly at higher altitudes.



High altitudes with a increase affinity for oxygen.


How does HbF turn into HbA?

The beta subunit is substituted for some alternative subunit like the gamma subunit.


Hemoglobin S is also known as?

Sickle cell anemia

Protein is precipitating inside RBC causing it to elongate and not flexible and clogs arteries and are rigid.

The protein that is precipitating is Hemoglobin itself.


Sickle Hemoglobin

Glu turns into Val

Causes hydrophobic pockets on surface of hemoglobin, which causes them to cluster and form elongated filaments...,filaments crystallize.... And form strands that elongate RBC

Hemoglobin precipitates because there is a single hemoglobin substitution.

Glu on beta chain at position 6 turns into Valene (much less polar)


Which of the following is not correct concerning 2,3- Bisphosphoglycerate (BPG)?

It increases the affinity of hemoglobin for oxygen.


Sickle cell

Decreases chances of malaria

Have increase survival advantage


The amino acid substitution of Val for Glu in Hemoglobin S results in aggregation of the protein because of ______ interactions between molecules.