Hemoglobin: Difference between revisions
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Each individual <scene name='Hemoglobin~Deoxyheme~1'>heme</scene> molecule contains one | Each individual <scene name='Hemoglobin~Deoxyheme~1'>heme</scene> molecule contains one | ||
<scene name='Hemoglobin~Deoxyheme_fe~2'>Fe2+</scene> atom. In the lungs, where oxygen is abundant, an <scene name='Hemoglobin~Oxyheme_fe~ | <scene name='Hemoglobin~Deoxyheme_fe~2'>Fe2+</scene> atom. In the lungs, where oxygen is abundant, an <scene name='Hemoglobin~Oxyheme_fe~2'>elemental oxygen molecule</scene> binds to the ferrous iron atom of the heme molecule and is later released in tissues needing oxygen. The heme group binds oxygen while still attached to the <scene name='Hemoglobin~Oxysubunit~2'>hemoglobin monomer</scene>. The spacefill view of the hemoglobin polypeptide subunit with an oxygenated heme group shows how the <scene name='Hemoglobin~Oxysubunitsf~1'>oxygenated heme group is held</scene> within the polypeptide. | ||
Anchoring of the heme is facilitated by a histidine nitrogen that binds to the iron. A second histidine is near the bound oxygen. the "arms" (propanoate groups) of heme face are hydrophilic and face the surface of the protein while the hydrophobic portions of the heme are buried among the hydrophobic amino acids of the protein. We can also view the anchored heme with the hemoglobin polypeptide subunit shown in a spacefill representation. | Anchoring of the heme is facilitated by a histidine nitrogen that binds to the iron. A second histidine is near the bound oxygen. the "arms" (propanoate groups) of heme face are hydrophilic and face the surface of the protein while the hydrophobic portions of the heme are buried among the hydrophobic amino acids of the protein. We can also view the anchored heme with the hemoglobin polypeptide subunit shown in a spacefill representation. | ||
Revision as of 20:57, 11 October 2007
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Hemoglobin is an oxygen-transport protein. Hemoglobin is an allosteric protein. It is a tetramer composed of two types of subunits designated α and β, whose stoichiometry is . The of hemoglobin sit roughly at the corners of a tetrahedron, facing each other across a at the center of the molecule. Each of the subunits prosthetic group. The give hemoglobin its red color.
Each individual molecule contains one atom. In the lungs, where oxygen is abundant, an binds to the ferrous iron atom of the heme molecule and is later released in tissues needing oxygen. The heme group binds oxygen while still attached to the . The spacefill view of the hemoglobin polypeptide subunit with an oxygenated heme group shows how the within the polypeptide.
Anchoring of the heme is facilitated by a histidine nitrogen that binds to the iron. A second histidine is near the bound oxygen. the "arms" (propanoate groups) of heme face are hydrophilic and face the surface of the protein while the hydrophobic portions of the heme are buried among the hydrophobic amino acids of the protein. We can also view the anchored heme with the hemoglobin polypeptide subunit shown in a spacefill representation.