The Structure of Normal Human Hemoglobin

Hemoglobin is a complex protein that has what is called a tetrameric structure—meaning it is made up of four globin subunits. The prevailing hemoglobin in adults is made up of two subunits labeled alpha (α), and two labeled beta (β). They derive from respective α and β globin gene regions containing ancient gene duplications serving unique purposes. Each globin subunit carries an iron-containing heme group, the “business center” where oxygen binding and release occur.