Hemoglobin subunit (deoxy form) (Hb (deoxyHb))

Deoxyhemoglobin is the form of hemoglobin in which the iron atom of each heme group is in the ferrous (Fe²⁺) state and is not bound to oxygen. It predominates in venous blood and is responsible for the dark red (bluish) color of deoxygenated blood. Hemoglobin tetramers consist of two alpha and two beta subunits, each containing a heme group able to bind oxygen reversibly[2][6][9]. In the deoxy state (the "tense" or "T" state), the molecule has a lower affinity for oxygen due to a particular quaternary conformation, stabilized by salt bridges and hydrogen bonds that are disrupted during oxygen binding[1][3]. Deoxyhemoglobin plays a central physiological role in transporting oxygen from the lungs to peripheral tissues and facilitating carbon dioxide return. It is not itself a drug target in the typical sense (receptor, enzyme, transporter), though its properties and concentration are relevant in diseases such as sickle cell anemia and hypoxic states[7][9]. Some experimental drugs, such as RSR-13, target deoxyhemoglobin allosterically to increase oxygen release, but generally, it is not considered a classic therapeutic target[5]. The term "deoxyhemoglobin" refers to a conformational state of the hemoglobin protein, not a unique gene or pharmacological receptor, so it is not a canonical therapeutic target.

Other names

Deoxyhemoglobindeoxy-HbdeoxyHbdeoxyhemoglobin Aunligated hemoglobinT state hemoglobin

Allosteric modulation of oxygen-binding affinity[5] Gas binding/displacement at heme iron