Final answer:
Myoglobin, especially oxymyoglobin, has the highest oxygen-binding affinity compared to the various forms of hemoglobin listed because of its stable oxygen-binding capacity at low partial pressures.
Step-by-step explanation:
The question is asking which molecule has the highest oxygen binding. To answer this, we need to understand how hemoglobin and myoglobin bind oxygen. Hemoglobin is a protein found in red blood cells that contains four globin proteins, each with a heme group that can bind one molecule of oxygen. Myoglobin is a protein found in muscle cells that has a higher affinity for oxygen than hemoglobin and is responsible for storing oxygen in muscle tissues.
Hemoglobin A1, Hemoglobin A2 and Hemoglobin S are different forms of hemoglobin. Hemoglobin F is another form of hemoglobin, primarily found in fetuses, which has a higher affinity for oxygen than adult hemoglobin. The oxygen affinity of hemoglobin increases with its state of oxygen saturation due to a phenomenon called cooperativity, but myoglobin does not exhibit this property because it lacks quaternary structure—it is a single polypeptide chain.
Given these properties, myoglobin, specifically oxymyoglobin, generally has the highest oxygen binding affinity because it can hold onto oxygen even at low partial pressures where hemoglobin would release it. Therefore, the correct answer is e. Myoglobin.