Recent studies have shown that the H-bond between the distal histidine and oxygen molecule in myoglobin has a strength of ~ 15 kJ/mol, but in hemoglobin, the strength of the bond is only ~8 kJ/mol. What does this suggest about the differences between myoglobin and hemoglobin?
A)myoglobin binds oxygen more strongly than hemoglobin
B)hemoglobin binds oxygen more strongly than myoglobin
C)the iron in myoglobin is more easily oxidized than in hemoglobin
D)the iron in hemoglobin is more easily oxidized than in myoglobin
E)none of the above

Question

Quizplus · Accepted Answer

The strength of the H-bond between the distal histidine and oxygen molecule in myoglobin is stronger than in hemoglobin. This suggests that myoglobin is able to bind oxygen more strongly than hemoglobin, which is consistent with the fact that myoglobin is a single-subunit protein that has a high affinity for oxygen and is used to store oxygen in muscle tissue, while hemoglobin is a tetrameric protein that is used to transport oxygen throughout the body. The weaker H-bond in hemoglobin allows for easier release of oxygen to tissues in need.

Recent Studies Have Shown That the H-Bond Between the Distal