Review Lecture - Stereochemical mechanism of oxygen transport by haemoglobin
1980; Royal Society; Volume: 208; Issue: 1171 Linguagem: Inglês
10.1098/rspb.1980.0047
ISSN2053-9193
Autores Tópico(s)Heme Oxygenase-1 and Carbon Monoxide
ResumoSpectroscopic and chemical evidence speak in favour of the iron-oxygen bond being polar. X-ray analysis shows that the oxygen molecule is inclined at an angle of about 115° to the haem plane. Cooperative binding of oxygen by haemoglobin is due to an equilibrium between two alternative structures, which differ in oxygen affinity by the equivalent of 3-3.5 kcal/mol. I proposed that in the low affinity structure the globin opposes the movement of the iron atom from its five-coordinated pyramidal geometry in the haem of deoxyhaemoglobin to its six-coordinated planar geometry in the haem of oxyhaemoglobin, while in the high affinity structure this restraint is absent. Recent evidence supporting this mechanism is described.
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