Myoglobin and Hemoglobin Flashcards
Where is Myoglobin normally found? And what is its purpose? (Simple explanation)
In muscle cells.
To store oxygen (like a battery!).
What is the structure of Myoglobin? What’s the key structure to the molecules function.
An all alpha(helix) protein.
Contains 8 alpha-helices.
Key Structure: Iron containing heme group. (In red)
What structure is this molecule?
Oxy-myoglobin heme group. (So myoglobin heme group storing oxygen)
NOTE it’s bonded to F8 and yet that is!
What side chains are around the heme of myoglobin? How are they configured?
Define “The fractional saturation”
The number of binding sites of a protein that are occupied by the ligand or by the small molecule.
What does pO2 stand for?
Partial pressure of O2.
What is the pO2 is venous blood?
~30torr;
Convert 1 atmosphere to mm Hg and torr.
Both = 760
Where is hemoglobin found? And what’s its purpose?
In red blood cells.
Job is to transport blood from lungs to other organs and lungs to muscle.
What is the structure of Hemoglobin?
Hb has four myoglobin-like subunits.
2 Hb chains are called alpha-chains , the other two are beta-chains. Alpha have same sequence as each other, same for betas.
This means Hb is much more complex then myoglobin.
Hemoglobin is a complex structured molecule. Why do we say that?
Results in cooperativiry: As a result of cross-talk between these four subunits, the oxygen binding curve of hemoglobin is not hyperbolic but “S” (sigmoidal) shaped.
Meaning increase efficiency of oxygen transport from lung to other organs.
What are two ways oxygen affinity is changed. (Brief)
pH change
Can be regulated allosterically by BPG.
What structure is this? Hint: oxygenated or not?
T-Stats
What structure is this? Hint: oxygenated or not?
R-State
When changing hemoglobin confirmation for oxygenated to deoxygenated, what level(s) of structure change. What do we need to know about the two different states.
R= Relaxed state: Salt bridges are broken. (Lower in free energy state when oxygen IS present.)
T= Tense State: Several Salt bridges (lower in free energy when NO oxygen present)
Transition doesn’t break symmetry!
Upon oxygenation explain how DeoxyHb molecularly transitions to Oxy Hb
