where is hemoglobin found
hemoglobin (hÄËmÉglÅËbÄ­n) [ key ], respiratory protein found in the red blood cells (erythrocytes) of all vertebrates and some invertebrates. A hemoglobin molecule is composed of a protein group, known as globin, and four heme groups, each associated with an iron atom.In the lungs, each iron atom combines reversibly with a molecule of oxygen. Each hemoglobin molecule also has attached a single cysteine amino acid, which attracts nitric oxide from the lungs. hemoglobin molecule is composed of a protein group, known as globin, and four heme groups, each associated with an iron atom. In the lungs, each iron atom combines reversibly with a molecule of oxygen.
Hemoglobin is also found outside red blood cells and their progenitor lines. Other cells that contain hemoglobin include the A9 dopaminergic neurons in the substantia nigra, macrophages, alveolar cells, and mesangial cells in the kidney. Hemoglobin S (Î± 2 Î² S 2) â A variant form of hemoglobin found in people with sickle cell disease. 2  There is a variation in the Î²-chain gene, causing a change in the properties of hemoglobin, which results in sickling of red blood cells.