Examination of the human genome has revealed two additional globins, both of which are monomeric proteins, more similar to myoglobin than to hemoglobin. WHat are they?
in the brain and retina; play a role in protecting neural tissues from hypoxia
more expressed throughout the body
In both, the proximal and distal histidines are coordinated to be iron atom in the deoxy form. Oxygen binding displaces the distal histidine.