5. Oxygen Delivery: Hemoglobin is a remarkable protein that is responsible not only for the
delivery of oxygen to tissues, but also the removal of CO2. Due to the unique function of
this protein it is highly regulated to be sensitive to environmental conditions. A primary
effector of O2 binding is CO2, which is able to affect hemoglobin via two different
mechanisms.
a) One mechanism is via allosteric binding to the amino terminal of the a subunit. The binding
affects the overall structure of the protein and alters the oxygen binding curve. Draw the
reaction of the amino terminus (hint: treat the amine as an –NH2 nucleophile) with CO2 to
produce a carbamate and a proton.
b) Using the equilibrium expression for allosteric effectors presented in class to sketch a rough
oxygen binding curve a) under normal conditions and b) under elevated CO2 conditions.
R-NH2
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(02
-
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p.
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tHT
ideation.
o elevation
POz
