What is the affinity of R-form hemoglobin for O2?

R-form hemoglobin, or the relaxed state of hemoglobin, has a high affinity for oxygen (O2). This is due to its structural conformation, which allows for optimal binding of oxygen molecules. In the R state, hemoglobin's quaternary structure changes in a way that enhances the interactions of the heme groups with oxygen, thus facilitating better transport of oxygen from the lungs to the tissues.

In contrast to the T-form, or tense state, of hemoglobin, which has a lower affinity for oxygen and is more suitable for releasing oxygen in the tissues, the R state is designed for oxygen uptake in the lungs. This difference in affinity is crucial for the efficient functioning of hemoglobin as an oxygen carrier in the body. Factors such as pH, carbon dioxide concentration, and temperature can influence the shift between these states, but in its R-form, hemoglobin is characterized by a strong attraction to oxygen.