Hemoglobin And Sickle Cell Disease - 1793 Words

Ana-Maria Sutac Biochemistry 370 11/13/2015 Hemoglobin and Sickle Cell Disease Introduction Sickle cell disease, also known as SCD, is a hereditary blood disorder that takes place due to mutation in the hemoglobin gene that is found in red blood cells. While it is said to have originated in Africa and is mostly predominant in African Americans, sickle cell disease is now common among different ethnic groups all over the world. Sickle cell anemia (HbSS) infects â€Å"an estimated 70,000 to 100,000 Americans†(Housman) and accounts for approximately 70% of anemia in the United States. Hemoglobin functions as an oxygen carrying protein as it carries oxygen from the lungs through the arteries and to the rest of the body. In sickle cell disease,†¦show more content†¦These subunits are held together by ionic, hydrogen bonds, van der Waals forces, hydrophobic interactions as well as heme groups that are made up of Fe2+. Hemoglobin can be found in two different states. The first state is known as the T-state when it is tense and oxygen deprived. The second state is known as R-state when is relaxed and oxygenated. Hemoglobin first binds to oxygen then transports it to blood vessels, which have low oxygen levels. After it releases the oxygen the blood vessels, the red cells then transports carbon dioxide (CO2) from the tissues to the lungs where it picks oxygen once more. Cooperativiy, Affinity, and Efficiency When a subunit binds to oxygen, it changes it conformation and sends messages to other subunits to bind to oxygen as well. When more hemoglobin monomers (subunits) bind to oxygen, it is increasing hemoglobin’s affinity to oxygen, thus leading to better cooperativity. It was also discovered that there is a higher affinity for purified hemoglobin rather than the hemoglobin inside the red blood cells due to the anionic compound 2,3-bisphosphoglycerate (2,3-BPG). This molecule binds to hemoglobin in a small pocket only found in the T state when it is deoxygenized and allows it become stable. It further causes a reduction in hemoglobin’s affinity to oxygen, working out in its favor. During the transition from T to R state, the pocket containing 2,3-BPG is broken and