Hemoglobin: Difference between revisions
Jump to navigation
Jump to search
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
<StructureSection load='1gzx' size='350' side='right' caption="Human Hemoglobin α chain (grey and pink) β chain (green and yellow) with bound O2 [[1gzx]]" scene="Hemoglobin/Foursubunits/5" > | <StructureSection load='1gzx' size='350' side='right' caption="Human Hemoglobin α chain (grey and pink) β chain (green and yellow) with bound O2 [[1gzx]]" scene="Hemoglobin/Foursubunits/5" > | ||
== Function == | == Function == | ||
'''Hemoglobin''' is an oxygen-transport protein. Hemoglobin is an | '''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, with stoichiometry <scene name='Hemoglobin/Alpha2beta2/7'>α2β2</scene>. The <scene name='Hemoglobin/Foursubunits/5'>four subunits</scene> of hemoglobin sit roughly at the corners of a tetrahedron, facing each other across a <scene name='Hemoglobin/Cavity/9'>cavity</scene> at the center of the molecule. Each of the subunits <scene name='Hemoglobin/Bbsubunitswithheme/5'>contains a heme</scene> prosthetic group. The <scene name='Hemoglobin/4heme/3'>heme molecules</scene> give hemoglobin its red color. | ||
Each individual <scene name='Hemoglobin/Deoxyheme/8'>heme</scene> molecule contains one <scene name='Hemoglobin/Deoxyheme_fe/9'>Fe2+</scene> atom. In the lungs, where oxygen is abundant, an <scene name='Hemoglobin/Oxyheme_fe/7'>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/8'>hemoglobin monomer</scene>. The spacefill view of the hemoglobin polypeptide subunit with an oxygenated heme group shows how the <scene name='Hemoglobin/Oxysubunitsf/4'>oxygenated heme group is held</scene> within the polypeptide. | Each individual <scene name='Hemoglobin/Deoxyheme/8'>heme</scene> molecule contains one <scene name='Hemoglobin/Deoxyheme_fe/9'>Fe2+</scene> atom. In the lungs, where oxygen is abundant, an <scene name='Hemoglobin/Oxyheme_fe/7'>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/8'>hemoglobin monomer</scene>. The spacefill view of the hemoglobin polypeptide subunit with an oxygenated heme group shows how the <scene name='Hemoglobin/Oxysubunitsf/4'>oxygenated heme group is held</scene> within the polypeptide. | ||