Role of hemoglobin structural-functional relationships in oxygen transport.

The molecular mechanism of O2 binding to hemoglobin (Hb) has been critically reviewed on the basis of the information built up in the last decades. It allows to describe in detail from the kinetic and thermodynamic viewpoint the process of O2 uptake in the lungs and release to the tissues, casting some light on the physiological and pathological aspects of this process. The relevance of structural-functional relationships for O2 binding is particularly outlined in the case of poorly vascularized tissues, such as retina, briefly discussing of strategies employed for optimization of oxygen supply to this type of tissues.