Hemoglobin cooperative oxygen binding

Eaton, W. A., Henry, E. R., Hofrichter, J., Mozzarelli, A. 1999. Is cooperative oxygen binding by hemoglobin really understood Nat. Struct. Biol. 6, 351-358. 

There is general appreciation that the principal quaternary structural changes giving rise to cooperative oxygen binding occur at the a P (and a p ) interfaces. For example, ""The quaternary structural change preserves hemoglobin s exact two-fold symmetry and takes place entirely across its (and o3 P ) interface. 

The interest in the structure-function relationship in hemoglobin has been primarily focused on the molecular mechanism of the cooperative oxygen binding. The main relevant structural information related to this problem was the differences observed between the oxy and deoxy structures of hemoglobin. However, little is known about the structure of the intermediately oxygenated hemoglobin molecules. Several models have therefore been proposed in order to... 

Table 2. Number of States (N) and Number of Parameters (N ) of Selected Models of Cooperative Oxygen Binding o Hemoglobin.

Svetina, S., 1973, Thermodynamical studies of cooperative oxygen binding by hemoglobin, m "Proc. VII. Internationales Symposium liber Strukture und Funktion der Erytrozyten", Anhand-lungen der Akademie der Wissenschaften der DDR, Berlin, p. 135. 

We can determine quantitatively the physiological significance of the sigmoid nature of the hemoglobin oxygen-binding curve, or, in other words, the biological importance of cooperativity. The equation... 

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