Hemoglobin zeta: Proteins and Enzymes

Hemoglobin is a tetrameric protein that serves as the oxygen transporter in red blood cells. Two alpha chain and two beta chains comprise the adult form of the molecule, with each subunit containing a heme group, or oxygen binding site. Sickle cell anemia is caused by a single amino acid change in the beta chain, which alters the solubility of the deoxygenated form of the molecule and causes the formation of long fibers that distort the red blood cell into the characteristic sickle shape. Thalassemias, another set of genetic diseases associated with hemoglobin, result from absence or deficiency in one of the hemoglobin chains.