Hemoglobin is a protein complex found in red blood cells that is responsible for transporting oxygen. It is not a single protein that is responsible for hemoglobin; rather, hemoglobin is the protein itself, composed of multiple protein subunits.
Understanding Hemoglobin
Hemoglobin is classified as a type of metalloprotein, a protein that contains a metal ion (in this case, iron within the heme group). It is also a chromoprotein due to its color and a globulin, referring to its spherical shape. Its primary function is oxygen-transport, binding to oxygen in the lungs and releasing it in tissues throughout the body.
Protein Subunits of Hemoglobin
The core structure of hemoglobin consists of protein chains known as globin. In adult humans, the most common form of hemoglobin (Hemoglobin A) is made up of four globin subunits: two alpha (α) chains and two beta (β) chains. Each of these globin subunits is a polypeptide chain synthesized under the control of specific genes.
The specific subunits, their genes, and chromosomal locations, as referenced, are:
| Subunit Name | Gene | Chromosomal Locus |
|---|---|---|
| Hb-α1 | HBA1 | Chr. 16 p13.3 |
| Hb-α2 | HBA2 | Chr. 16 p13.3 |
| Hb-β | HBB | Chr. 11 p15.5 |
Attached to each globin subunit is a molecule called heme. Hemoglobin contains four heme cofactors, each containing an iron atom. It is this iron atom within the heme group that directly binds to oxygen molecules. The globin subunits provide the structural framework that holds the heme groups and regulates their function.
In essence, hemoglobin is a sophisticated assembly of globin protein chains and heme groups working together to perform the vital task of oxygen delivery in the bloodstream.
For more details, you can refer to the Hemoglobin Wikipedia page.
