What is Hemoglobin?

Hemoglobin (Hb) is a protein, which is contained in the red blood cells. Hb is a round-shaped protein, consisting of 4 subunits (tetramer). De 4 subunits or globines (a- and b-globins) are proteins chains of about 140 amino acids, each of them containing an iron atom (click here to look at the Hb-tetramer). The 4 iron atoms and a shape modifying mechanism allow the hemoglobin tetramer to transport oxygen from the lung to the tissues and carbon dioxide in the opposite direction. The life span of the red cell is about 4 months, which means that, in order to provide enough hemoglobin to fill the new red cells, 1 kg of hemoglobin must be produced each 4 months. Thus during our life we need to make about 250-300 kg (550-660 lbs) of this essential protein. Low hemoglobin (low Hb) is a sign of anemia. Often a low Hb may be associated with tiredness and may be induced by iron deficiency hence, anemia complains often disappear after iron medication. Many person, mainly with Mediterranean, African or Asian ancestors may be carriers, often without complains, of a hereditary form of anemia (Thalassemia) of abnormal Hb (HbS). This is due to the fact that carriers of thalassemia or HbS are protected in their early age from the fatal consequences of malaria tropica infections. People with mild anemia, not improving after iron therapy may be carriers of thalassemia, HbS or other forms of hereditary anemias. Carrier diagnosis is easily done by a simple blood analysis and it is extremely important for healthy carriers to be diagnosed. This because healthy parents, both carriers of thalassemia or HbS are at risk for severe and incurable forms of hereditary anemia's in their children that may receive both affected genes from the parents (Click here for information about hereditary risk).