NCIt definition : The red respiratory protein of erythrocytes, consisting of approximately 3.8% heme
and 96.2% globin (64.5 KD), which as oxyhemoglobin (HbO2) transports oxygen from the
lungs to the tissues where the oxygen is readily released and HbO2 becomes Hb.;
Alternative definition : NCI-GLOSS: The substance inside red blood cells that binds to oxygen in the lungs
and carries it to the tissues.;