Hemoglobin and Myoglobin Flashcards
What group is responsible for the oxygen binding capacity of hemoglobin?
Heme group
What surrounds heme and protects the ferrous form from getting oxidized?
Globin
If Fe2+ is oxidized what does it become?
Methomoglobin
What facilitates oxygen storage in the muscle?
Myoglobin
When looking at a graph what kind of curve will Myoglobin have?
Hyperbolic
How many molecules of oxygens can hemoglobin bind to?
4 molecules of oxygen
What enzyme works together with Hemoglobin to remove acidity from the tissues?
Carbonic anhydrase
When looking at a graph in what type of fashion will hemoglobin plot?
sigmoidal
A change in confirmation of T to R will increase what?
O2 affinity
What does it mean when one says Oxygen binding is cooperative?
It means when Alpha 1 subunit is oxygen bound each subsequent oxygen binds with higher affinity that the previous. Similarly When one oxygen dissociates the other three will dissociate faster
At which state does 2,3-BPG like to bind?
Tort state (deoxyhemoglobin)
Lower pH favors T state which will cause what to Hemoglobin?
To release its Oxygen
The release of what reinforces the Bohr effect?
CO2 because it lowers the pH
When Iron becomes oxidized what condition is that called?
Methemoglobinemia
Methemoglobinemia may result from 5 things. What are they?
1) Poisoning with oxidizing agents
2) Oveproduction of oxidants by enzymes
3) Failure of a cell to make glutathione (reduces oxidants)
4) Histidine of hemoglobin being replaced by tyrosine
5) methemoglobin reductase deficiency
In the presence of CO (carbon monoxide) what does it do?
reversibly binds to Hemoglobin, which inhibits the release of oxygen from 2-4 heme units.
Carbon monoxide is an example of what kind of effector?
Positive allosteric
Carbon Dioxide is and example of what kind of effector?
Negative allosteric ( release of oxygen)
When a patient has been expose to sublethal levels or Carbon monoxide he is place in a hyperbaric chamber. Why is this effective?
Being put in a high pressure chamber directs CO to bind at an angle instead of linearly so it weakens its affinity
In higher altitude BPG favors which State and why?
BPG favors the Tort state because since higher altitude has less oxygen for the tissues it forces Hb to release to oxygen to generate more energy for the tissues.
On a graph BPG will move to what side?
Right
Once hemoglobin is stripped of BPG it acts similar to what and why
SIMILar to myoglobin which has little propensity to release oxygen
Describe why Fetal hemoglobin cannot bind to 2,3BPG
Fetal Hb has replaced its His to Ser (which is less positive) so fetal Hb has a lower binding affinity to 2,3BPG compared to adults.
Where would you find higher oxygen saturation in a pregnant patient ?
Fetus
Fetal hemoglobin binds oxygen with greater affinity than adult hemoglobin because the fetus has lower affinity to what?
2,3-BPG ( remember the gamma chains of fetal hemoglobin each have a histidine residue replaced by a serine residue which cannot form salt bonds)
The tort state is stabilized by what kind of bonds?
Salt bonds
Majority of the carbon dioxide that is formed during metabolism is transported to the lungs in the blood by what ion?
bicarbonate ion
When does myoglobin have a higher affinity for Oxygen when compared to the affinity of hemoglobin?
at lower partial pressures
