BIOCHEMISTRY 3521
 Study Guide #3 -- Oxygen Carriers and Allosterics 
Material Provided in part by R. Morse (ILSTU, Chem 242)
Also from Biochemistry 460 at Arizona

1.  List the major features of the 3-D structures of myoglobin and hemoglobin. How do they differ? How are they similar?
 
2. Compare and contrast hemoglobin and myoglobin regarding:
a) Quaternary structure
b) Cooperativity in oxygen binding
c) Effect of pH on oxygen binding

3.  What is meant by positive cooperativity in oxygen binding to hemoglobin?

What is the structural and energetic basis for this phenomenon?
What is its physiological significance?
How does 2,3-BPG influence oxygen binding to hemoglobin
 

4. Describe the Bohr effect (H+ and CO2) in oxygen binding to hemoglobin.

What is its physiological significance?
What is the structural basis for these phenomena?
How does 2,3-BPG influence oxygen binding to hemoglobin, and what is the structural basis for this?
What would happen to 1) our ability to transport oxygen and 2) release oxygen to our tissues if levels of 2,3-BPG decreased?
Under what physiological conditions might a decrease in 2,3-BPG be beneficial?
 

5. Describe the major structural differences between the oxy and deoxy forms of hemoglobin.

What is the structural basis for the triggering of the switch in quaternary structure from T to R in hemoglobin?

6. What is the structural and functional difference between normal and sickle cell hemoglobin? Relate this to the pathology of sickle cell anemia.

Thought Questions:

The amino acid substitution which causes sickle cell anemia does not affect the binding of oxygen to hemoglobin S very much.
Why then do people who have this amino acid substitution get sick?
Would you recommend as a course of treatment heavy exercise or bed rest? Why?
Would you expect these people to do well if they rested at high elevations? Why or why not?
 

7. Depending on time constraints we may not get far enough to cover material pertaining to the next question:

What is the structural and functional difference between the adult and fetal forms of hemoglobin?
Relate these to the physiological roles of these proteins.