hemoglobin
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GC: n

S: NCBI – https://bit.ly/32eaK2I (last access: 10 October 2019); MEDLP – https://bit.ly/2pkvIOH (last access: 10 October 2019).

N: 1. Also hæmoglobin, coloring matter in red blood cells, 1862, shortening of hæmatoglobin (1845), from Greek haimato-, combining form of haima (genitive haimatos) “blood” + globulin, a type of simple protein, from globule, formerly a word for “corpuscle of blood.”

  • Abbreviation: Hb.

2. Hemoglobin, also spelled haemoglobin, iron-containing protein in the blood of many animals—in the red blood cells (erythrocytes) of vertebrates—that transports oxygen to the tissues. Hemoglobin forms an unstable, reversible bond with oxygen; in the oxygenated state it is called oxyhemoglobin and is bright red; in the reduced state it is purplish blue.
3. Hemoglobin develops in cells in the bone marrow that become red blood cells. When red cells die, hemoglobin is broken up: iron is salvaged, transported to the bone marrow by proteins called transferrins, and used again in the production of new red blood cells; the remainder of the hemoglobin forms the basis of bilirubin, a chemical that is excreted into the bile and gives the feces their characteristic yellow-brown colour.
4. Each hemoglobin molecule is made up of four heme groups surrounding a globin group, forming a tetrahedral structure. Heme, which accounts for only 4 percent of the weight of the molecule, is composed of a ringlike organic compound known as a porphyrin to which an iron atom is attached. It is the iron atom that binds oxygen as the blood travels between the lungs and the tissues. There are four iron atoms in each molecule of hemoglobin, which accordingly can bind four atoms of oxygen. Globin consists of two linked pairs of polypeptide chains.

S: 1. OED – https://bit.ly/2Ma25IV (last access: 10 October 2019). 2 to 4. EncBrit – https://bit.ly/2ooLqZj (last access: 10 October 2019).

SYN: Hb, haemoglobin, blood pigment.

S: GDT – https://bit.ly/31aS6aw (last access: 10 October 2019)

CR: anemia, red blood cell.