Adult human hemoglobin (HbA)

Adult human hemoglobin (HbA) is the primary oxygen-transport metalloprotein found in red blood cells, characterized by a heterotetrameric structure consisting of two alpha (α) and two beta (β) globin chains (StatPearls, 2023). Each subunit contains a prosthetic heme group with a central iron atom capable of reversibly binding one molecule of oxygen (UniProt, 2024). Beyond oxygen delivery, HbA plays a vital role in transporting carbon dioxide and buffering blood pH through the Bohr effect. In clinical medicine, HbA is a major therapeutic target for hemoglobinopathies like sickle cell disease, where drugs like voxelotor stabilize the oxygenated state to inhibit the polymerization of mutant hemoglobin (FDA, 2019). It also serves as a critical diagnostic tool, with glycated hemoglobin (HbA1c) levels reflecting average blood glucose over several months (PubMed, 2021).

Other names

Hemoglobin AHbA1Alpha-2-beta-2 hemoglobinAdult hemoglobin

Allosteric modulation to increase oxygen affinity and stabilize the relaxed (R) state, or competitive binding at the heme iron site.