Hemoglobin (adult) (Hb or Hgb)

Hemoglobin is a **tetrameric metalloprotein** found predominantly in erythrocytes (red blood cells)[9]. It consists of four globin polypeptide chains, each with an iron-containing heme group, allowing one molecule of hemoglobin to bind up to four oxygen molecules cooperatively[1][4][7][8][9]. Hemoglobin binds oxygen in the lungs and releases it at tissues with lower oxygen tension, driven by allosteric changes influenced by pH, CO₂, temperature, and 2,3-bisphosphoglycerate levels[1][7][9]. This process is essential for aerobic metabolism in all tissues. Hemoglobin also plays a role in transporting carbon dioxide and regulating blood flow through interactions with nitric oxide[2][3]. Disorders of hemoglobin production, structure, or regulation lead to diseases such as anemia and hemoglobinopathies.

Other names

Hemoglobin (Hgb)Adult hemoglobinOxyhemoglobin (when oxygen-bound)Deoxyhemoglobin (when oxygen-unbound)

Increasing hemoglobin synthesis or stability (erythropoietin, iron) Enhancing oxygen binding/release dynamics (experimental) Reducing abnormal hemoglobin polymerization (hydroxyurea in sickle cell disease)