Hemoglobin S

Hemoglobin S is an abnormal hemoglobin that differs from hemoglobin A by the substitution of valino (Val) in the β-chain from glutamic acid (Glu) at the sixth position. With a high content of hemoglobins in the patient's body (that is, homozygote for hemoglobin S), sickle cell anemia can develop, which is why the blood takes on the shape of a sickle. Sickle cells can accumulate in the spleen and other organs, causing damage and dysfunction. To diagnose sickle anemia and determine the need for treatment, the patient is given a blood test for hemoglobin. Depending on the results of the examination, treatment with iron supplements or other medications may be prescribed. It is important to note that hemolytic anemia usually occurs silently, does not lead to acute heart failure and requires frequent visits to medical attention.

Hemoglobin S is a form of hemoglobin that is a genetically modified version of hemoglobin A. It differs from its normal counterpart by replacing glutamic acid (optically active) at the sixth position in the b-chain of globin with valine (not optically active). Hemoglobin C – reduces the oxygen content in the body and negatively affects health, because causes hypoxia. Sickle cell, or spherocytic, anemia is a hereditary disease that is caused by a mutation in the gene encoding the synthesis of hemoglobin, an element of red blood cells responsible for the delivery of oxygen to all tissues and organs. As a result of the mutation, a form of blood is produced that is unable to fully supply the organs with oxygen. Its content is always reduced; in response to this, the body begins to conserve oxygen, slowing down metabolic processes and organ function, redirecting more resources to survival.

The phenotype of the disease suggests that approximately 30% of children with sickle cell anemia

Hemoglobin S plays an important role in the physiology of humans and other mammals, especially in the regulation of hematopoiesis. It is the most abundant subunit globin in the bloodstream of healthy people, accounting for up to 97% of all hemoglobin. The hemoglobin a-peptide sequence contains a G→V mutation at the sixth position, which results in the replacement of the glutamine amino acid with valine. Hemoglobin S plays an important regulatory role during the acute phase of inflammation. Quantitative changes in the formation of Hb S reveal blood clotting disorders and latent forms of some anemias.

Hemoglobin S

In most normal red blood cells, Hb A consists of four tetramer polypeptide chains. One chain is α-globin and three chains are β-globins. A hemoglobin molecule (heme) is added to this structure to form a tetramer. In sickle disease, covalently bound hemoglobin (usually hemoglobin A), as a result of the replacement of the glutamic amino acid in the α-chains of the β-valentin chains (6 of these chains), can form a homotetramer in which two halves are located one below the other, forming a "C" in sickle shape.

Thus, for hemoglobin SA, two α-chains and two different types of β-chains lead to the formation of tetamers that perform the same function as hemoglobin AA. However, structurally it is significantly different: the valentine amino acid cross-links between chains to form a "C" shape, as opposed to the hemoglobin Ca A being in a spindle shape as in normal red blood cells. Both alternative states, i.e. normal and sickle cells exist in a state of equilibrium.

The polarity of the large number of hydrogen bonds between the covalent carbon pairs of both halves of hemoglobin Sa largely contributes to the fact that red blood cells have the ability to bend slightly. Consequently, when a crescent forms, a crescent-shaped formation occurs instead of the normal scarf shape. Typically, this unique form in homozygous cells (i.e., both β-ca chains) results in crescent-shaped cell helices