His87
His87 is a specific position within the human hemoglobin protein. Hemoglobin is a complex protein responsible for transporting oxygen from the lungs to the rest of the body and carbon dioxide back to the lungs. It is composed of four subunits, typically two alpha-globin chains and two beta-globin chains. Each subunit contains a heme group, which is an iron-containing molecule that binds to oxygen.
The notation "His87" refers to the 87th amino acid residue, which is histidine, in the beta-globin chain
Specifically, His87 in the beta-globin chain is known as the "proximal histidine." This residue is directly coordinated