Hemoglobin A (HbA)

Hemoglobin A is the principal adult form of hemoglobin, accounting for about 95–98% of hemoglobin in healthy adults. It is a tetrameric globular protein composed of two alpha and two beta chains (α2β2), each with a non-protein heme group containing iron that binds oxygen[2][3][6][7]. Located in red blood cells, hemoglobin A transports oxygen from the lungs to tissues and returns carbon dioxide from tissues to the lungs for exhalation[2][3][5][7]. The protein undergoes cooperative binding—its affinity for oxygen increases with each molecule bound, forming an S-shaped oxygen dissociation curve[7][9]. Mutations affecting the globin chains can lead to disorders such as sickle cell disease and β-thalassemia, altering its structure and function[3][6][9]. Hemoglobin A is not a direct drug target, but its glycosylated form (HbA1c) serves as a critical biomarker for long-term glucose control in diabetes[2][6]. Direct targeting of hemoglobin A with drugs is not standard; most interventions aim to correct or compensate for abnormal hemoglobin forms, or to treat consequences of impaired oxygen transport.

Other names

adult hemoglobinhemoglobin A1α2β2

Not applicable (HbA is not targeted directly by drugs; changes in its conformation due to mutation/disease may affect function)