Hemoglobin structure

We all know that the human body is made up of hemoglobin. The existence of hemoglobin is also very important to the human body. If the human body has abnormal hemoglobin, it will cause a variety of diseases. Many people choose to use blood tests when checking hemoglobin, because hemoglobin is composed of ferrous heme and globin. So what is the structure of hemoglobin?

Each hemoglobin molecule is composed of one molecule of globin and four molecules of heme, with globin accounting for about 96% and heme accounting for 4%.

Hemoglobin is a protein responsible for carrying oxygen in higher organisms.

Hemoglobin in the human body is composed of four subunits, two α subunits and two β subunits. In an electrolyte solution similar to the human body environment, the four subunits of hemoglobin can automatically assemble into an α2β2 form.

Each subunit of hemoglobin is composed of a peptide chain and a heme molecule. Under physiological conditions, the peptide chain will coil and fold into a sphere, holding the heme molecule inside. The spherical structure formed by the coiled peptide chain is also called globin. The heme molecule is a small molecule with a porphyrin structure. In the center of the porphyrin molecule, the nitrogen atoms on the four pyrrole rings in the porphyrin are coordinated to a ferrous ion, and the nitrogen atom on the indole side chain of a histidine residue at the 8th position in the globin peptide chain is coordinated to the ferrous ion from above the plane of the porphyrin molecule. When hemoglobin is not bound to oxygen, a water molecule is coordinated to the ferrous ion from below the porphyrin ring, and when hemoglobin carries oxygen, the oxygen molecule replaces the water molecule.

1 Structure: Hemoglobin (Hb) is composed of two pairs of globin peptide chains and 4 heme iron. Globin has four peptide chains (α and β chains); heme: protoporphyrin and iron. 2 Characteristics: (1) Under normal circumstances, 99% of Hb is reduced Hb (HbA) and 1% is ferric Hb (HbF). (2) Only Hb in the Fe2+ state can combine with oxygen, which is called oxygen-hemoglobin. (3) The types and proportions of Hb vary during different stages of human growth. Three months after birth, HbA>95%, while HbF drops below 1%. (4) Hemoglobin synthesis is regulated by hormones (erythropoietin, androgen). (5) The relative molecular mass is 64458. (6) The degradation products are globin and heme.