hemoglobin

(hē`məglō'bĭn), respiratory protein found in the red bloodblood,
fluid pumped by the heart that circulates throughout the body via the arteries, veins, and capillaries (see circulatory system; heart). An adult male of average size normally has about 6 quarts (5.6 liters) of blood.
..... Click the link for more information. cells (erythrocytes) of all vertebrates and some invertebrates. A hemoglobin molecule is composed of a protein group, known as globin, and four heme groups, each associated with an iron atom.

In the lungs, each iron atom combines reversibly with a molecule of oxygen. Each hemoglobin molecule also has attached a single cysteine amino acid, which attracts nitric oxide from the lungs. The enriched hemoglobin circulates and is carried through the body to the tissues, where the nitric oxide dilates the small capillaries, allowing hemoglobin to deliver its oxygen to the tissues. Then the oxygen- and nitric oxide–free hemoglobin molecule picks up carbon dioxide and free nitric oxide and transports both back to the lungs, where they are exhaled as waste.

Hemoglobin is produced in bone marrowbone marrow,
soft tissue filling the spongy interiors of animal bones. Red marrow is the principal organ that forms blood cells in mammals, including humans (see blood). In children, the bones contain only red marrow.
..... Click the link for more information. by erythrocytes and is circulated with them until their destruction. It is then broken down in the spleen, and some of its components, such as iron, are recycled to the bone marrow. Other components, such as the heme groups, are broken down into bilirubin, transported to the liver, and secreted with the bilebile,
bitter alkaline fluid of a yellow, brown, or green color, secreted, in man, by the liver. Bile, or gall, is composed of water, bile acids and their salts, bile pigments, cholesterol, fatty acids, and inorganic salts.
..... Click the link for more information. into the intestine for eventual elimination from the body.

Hemoglobin deficiency may be a result of structural abnormality in the hemoglobin molecules themselves. In sickle cell diseasesickle cell disease
or sickle cell anemia,
inherited disorder of the blood in which the oxygen-carrying hemoglobin pigment in erythrocytes (red blood cells) is abnormal.
..... Click the link for more information. , this structural abnormality creates malformed red blood cells which clog blood vessels, severely restricting the supply of blood flowing to body tissues.

Hemoglobin

The oxygen-carrying molecule of the red blood cells of vertebrates. This protein represents more than 95% of the solid constituents of the red cell. It is responsible for the transport of oxygen from the lungs to the other tissues of the body and participates in the transport of carbon dioxide in the reverse direction.

Each molecule of hemoglobin comprises four smaller subunits, called polypeptide chains. These are the protein or globin parts of hemoglobin. A heme group, which is an iron-protoporphyrin complex, is associated with each polypeptide subunit and is responsible for the reversible binding of one molecule of oxygen. The polypeptide chains and the heme are synthesized and combine together in nucleated red cells of the bone marrow. As these cells mature, the nuclei fragment and the cells, now called reticulocytes, begin to circulate in the blood. After sufficient hemoglobin has been formed in the reticulocyte, all nuclear material disappears and the cell is then called an erythrocyte, or red blood cell. Each hemoglobin molecule lasts as long as the red cell, which has an average life of 120 days. See Porphyrin

Normal adult males and females have about 16 and 14 g, respectively, of hemoglobin per 100 ml of blood; each red cell contains about 29 × 10^-12 g of hemoglobin. Red cells normally comprise 40–45% of the volume of whole blood.

The reversible combination of hemoglobin and oxygen can be represented by the reaction shown below. The equilibrium constants for each step are not the same because an oxygen molecule on one heme group changes the affinity of the other hemes for additional oxygen molecules. This alteration in binding affinity during oxygenation is called heme-heme interaction and is due to small changes in the three-dimensional structure of the molecule.

Hemoglobin combines reversibly with carbon monoxide about 210 times more strongly than with oxygen. This strong affinity for carbon monoxide accounts for the poisoning effects of this gas.

Hemoglobin binds carbon dioxide by means of free amino groups of the protein but not by the heme group. The reversible combination with carbon dioxide provides part of the normal blood transport of this gas. Hemoglobin serves also as a buffer by reversible reactions with hydrogen ions. The acidic property of oxyhemoglobin is greater than deoxygenated hemoglobin. The extra binding of hydrogen ion by deoxyhemoglobin promotes the conversion of tissue carbon dioxide into bicarbonate ion and thus increases the amount of total carbon dioxide which can be transported by blood. See Blood, Respiration

Hemoglobin

(Hb), a red iron-containing pigment in the blood of man, vertebrates, and some invertebrates.

The function of hemoglobin in the organism is the transport of oxygen (0₂) from the respiratory organs to the tissues; it also plays an important role in transporting gaseous carbon dioxide from the tissues to the respiratory organs. In most invertebrates hemoglobin is freely dissolved in the blood; in vertebrates and some invertebrates, it is present in the red blood cells (erythrocytes), constituting about 94 percent of their dry weight. The molecular weight of erythrocytic hemoglobin is about 66,000; the weight of the hemoglobin dissolved in plasma may be as much as 3,000,000. Chemically, hemoglobin is a complex chromoprotein consisting of the protein globin and the ferroporphyrin heme. In higher animals and man, hemoglobin consists of four subunits, or monomers, each with a molecular weight of about 17,000. Two of the monomers (alpha chains) contain 141 amino acid residues each; each of the other two (beta chains) contains 146 residues.

The spatial structures of these polypeptides are similar in many respects. They form characteristic “hydrophobic pockets” containing one heme molecule per subunit. Of the six coordinate bonds of the iron atom in heme, four are directed toward the nitrogen of the pyrrole rings; the fifth is connected to the nitrogen of the imidazole ring of histidine, a polypeptide that stands in the 87th position in the alpha polypeptide chain and 92nd in the beta chain; the sixth bond is directed toward a water molecule or other groups (ligands), including oxygen. The subunits are loosely bound to one another by hydrogen, salt links, and other noncovalent bonds, and they readily dissociate under the influence of amides and high salt concentrations, mostly to form symmetrical dimers (αβ) and partly to form alpha and beta monomers. The spatial structure of the hemoglobin molecule has been studied by X-ray diffraction analysis (M. Perutz, 1959).

The sequential positions of the amino acids in the alpha and beta chains of hemoglobin in a number of higher animals and man have been completely ascertained. In the tetrameric hemoglobin molecule all four heme residues are located on the surface and readily accessible to reaction with O₂. Oxygenation is ensured by the presence of the Fe²⁺ atom in heme. This reaction is reversible and depends upon the partial pressure (tension) of O₂. Hemoglobin combines with O₂ to form oxyhemoglobin (oxygenation) in the capillaries of the lungs, where O₂ tension is about 100 millimeters of mercury (mm Hg). Oxyhemoglobin dissociates to hemoglobin and O₂ in the capillaries of tissues, where O₂ tension is much lower (about 40 mm Hg). The freed oxygen enters the cells of organs and tissues, where the partial pressure of O₂ is still lower (5-20 mm Hg, within the cell diminishing almost to zero). The union of O₂ with hemoglobin and the dissociation of oxyhemoglobin to hemoglobin and O₂ are accompanied by changes in conformation of the hemoglobin molecule and by reversible breakdown into dimers and monomers, followed by aggregation into tetramers. (See Figure 1.)

Figure 1. Human oxyhemoglobin dissociation curve

Other properties of hemoglobin also change upon reaction with 0₂; oxygenated hemoglobin is an acid 70 times stronger than hemoglobin. This plays an important part in the binding of C0₂ in the tissues and its release in the lungs. Absorption bands in the visible part of the spectrum are characteristic: hemoglobin has a single maximum at 554 millimicrons (mμ) and oxygenated hemoglobin has two maxima (at 578 and 540 mμ). Hemoglobin can combine directly with C0₂ (as a result, of reaction with the NH₂ groups of globin) to form carbamino hemoglobin, an unstable compound that readily breaks down in the capillaries of the lung into hemoglobin and CO₂.

The amount of hemoglobin in human blood averages 13-16 gram percent (or 78-96 percent according to Sahli); females have somewhat less hemoglobin than males. The properties of hemoglobin change in the course of the organism’s development. The hemoglobin is therefore defined as either fetal (HbF) or adult (HbA). Fetal hemoglobin has a greater affinity for oxygen than does adult hemoglobin, a fact of great physiological significance in that it ensures greater stability in the fetal stage in cases of O₂ insufficiency. The determination of the amount of hemoglobin in the blood is important in characterizing the respiratory functions of the blood, both under normal conditions and in a great variety of diseases (especially in diseases of the blood). The amount of hemoglobin is determined by special devices called hemoglo-binometers.

In certain diseases and in congenital blood abnormalities (hemoglobinopathies), anomalous (pathological) hemoglobins appear in the red blood cells. These hemoglobins differ from the normal in the substitution of an amino acid residue in the alpha or beta chains. More than 50 kinds of anomalous hemoglobins have been identified. Sickle-cell anemia, for example, is characterized by the presence of hemoglobin in whose beta chains glutamic acid, which stands in the sixth position from the N-(amino-) terminus, is replaced by valine. Erythrocytic anomalies associated with hemoglobin F or hemoglobin H underlie the conditions of thalassemia and methemoglobinemia. The respiratory function of certain anomalous hemoglobins is severely impaired, giving rise to various pathological conditions (for example, anemias). The properties of hemoglobin may be altered by poisoning. Carbon monoxide, for example, stimulates the formation of car-boxyhemoglobin; other poisons may change the Fe²⁺ of heme into Fe³⁺, with the formation of methemoglobin. These hemoglobin derivatives are incapable of oxygen transport. The hemoglobins of various animals are species-specific because of the peculiar structure of the protein part of the molecule. The hemoglobin liberated upon the destruction of erythrocytes is utilized to form bile pigments.

Muscle tissue contains muscle hemoglobin (myoglobin), which is similar in molecular weight, composition, and properties to the subunits (monomers) of hemoglobin. Analogues of hemoglobin have been found in certain plants (for example, leghemoglobin, found in leguminous root nodules).

REFERENCES

Korzhuev, P. A. Gemoglobin. Moscow, 1964.
Haurowitz, F. Khimiia i funktsii belkov, 2nd ed. Moscow, 1965. Pages 303-23. (Translated from English.)
Ingram, V. Biosintez makromolekul. Moscow, 1966. Pages 188-97. (Translated from English.)
Rapoport, S. M. Meditsinskaia biokhimiia. Moscow, 1966. (Translated from German.)
Perutz, M. “Molekula gemoglobina.” In the collection Molekuly i kletki. Moscow, 1966. (Translated from English.)
Zuckerkandl, E. “Evoliutsiia gemoglobina.” In the collection Molekuly i kletki. Moscow, 1966.
Fanelli, A. R., E. Antonini, and A. Caputo. “Hemoglobin and Myoglobin.” Advances in Protein Chemistry, 1964, vol. 19, pp. 73-222.
Antonini, E., and M. Brunori. “Hemoglobin.” Annual Review of Biochemistry, 1970, vol. 39, pp. 977-1042.

G. V. ANDREENKO and S. E. SEVERIN

hemoglobin

[′hē·mə‚glō·bən] (biochemistry) The iron-containing, oxygen-carrying molecule of the red blood cells of vertebrates comprising four polypeptide subunits in a heme group.

haemoglobin

(US), hemoglobin a conjugated protein, consisting of haem and the protein globin, that gives red blood cells their characteristic colour. It combines reversibly with oxygen and is thus very important in the transportation of oxygen to tissues

Hemoglobin

hemoglobin

[he´mo-glo″bin] the main functional constituent of the red blood cell, serving as the oxygen-carrying protein; it is a type of hemoprotein" >hemoprotein in which each molecule is a tetramer composed of four monomers held together by weak bonds. It consists of two pairs of polypeptide chains, the globins, each having an attached heme molecule composed of iron plus a protoporphyrin molecule. Symbol Hb.Chemistry and Physiology. The iron atom has a free valence and can bind one molecule of oxygen. Thus, each hemoglobin molecule can bind one molecule of oxygen. The binding of oxygen by one monomer increases the affinity for oxygen of the others in the tetramer. This makes hemoglobin a more efficient transport protein than a monomeric protein such as myoglobin.
Oxygenated hemoglobin (oxyhemoglobin) is bright red in color; hemoglobin unbound to oxygen (deoxyhemoglobin) is darker. This accounts for the bright red color of arterial blood, in which the hemoglobin is about 97 per cent saturated with oxygen. Venous blood is darker because it is only about 20 to 70 per cent saturated, depending on how much oxygen is being used by the tissues. The affinity of hemoglobin for carbon monoxide is 210 times as strong as its affinity for oxygen. The complex formed (carboxyhemoglobin) cannot transport oxygen. Thus, carbon monoxide poisoning results in hypoxia and asphyxiation.
Another form of hemoglobin that cannot transport oxygen is methemoglobin, in which the iron atom is oxidized to the +3 oxidation state. During the 120-day life span of a red blood cell, hemoglobin is slowly oxidized to methemoglobin. At least four different enzyme systems can convert methemoglobin back to hemoglobin. When these are defective or overloaded, methemoglobinemia can result, with high methemoglobin levels causing dyspnea and cyanosis.
A secondary function of hemoglobin is as part of the blood buffer system. The histidine residues in the globin chains act as weak bases to minimize the change in blood pH that occurs as oxygen is absorbed and carbon dioxide released in the lungs and as oxygen is delivered and carbon dioxide taken up from the tissues.
As erythrocytes wear out or are damaged, they are ingested by macrophages of the reticuloendothelial system. The porphyrin ring of heme is converted to the bile pigment bilirubin, which is excreted by the liver. The iron is transported to the bone marrow to be incorporated in the hemoglobin of newly formed erythrocytes.
The hemoglobin concentration of blood varies with the hematocrit. The normal values for the blood hemoglobin concentration are 13.5 to 18.0 g/100 ml in males and 12.0 to 16.0 g/100 ml in females. The normal concentration" >mean corpuscular hemoglobin concentration, which is the concentration within the red blood cells, is 32 to 36 g/100 ml.Variant and Abnormal Hemoglobins. There are six different types of globin chains, designated by the Greek letters α, β, γ, δ, ε, and ζ. The composition of a hemoglobin is specified by a formula such as α₂β₂, which indicates a tetramer containing two α chains and two β chains. The chains are coded by different genes, which are turned on and off during development in order to produce hemoglobins with the oxygen-carrying properties required at each developmental stage. In the first three months of embryonic development, when blood cells are produced in the yolk sac, embryonic hemoglobins such as Hb Gower (α₂^Aε₂) or Hb Portland (ζ₂γ₂) are produced. As erythropoiesis shifts to the liver and spleen, the fetal hemoglobin Hb F (α₂γ₂) appears. When erythropoiesis shifts to the bone marrow during the first year of life, the adult hemoglobins Hb A (α₂β₂) and Hb A₂ (α₂δ₂) begin to be produced.
Many abnormal hemoglobins arising from mutations have been discovered. Some have altered oxygen affinity, some are unstable, and in some the iron atom is oxidized, resulting in congenital methemoglobinemia. Some mutations result in a reduced rate of hemoglobin synthesis. All such conditions are known as hemoglobinopathies.
The most common hemoglobinopathy is sickle cell disease, caused by a mutation replacing the sixth amino acid in the β chain, normally glutamic acid, by valine. The variant hemoglobin α₂β^S₂ is known as Hb S. Mutations resulting in reduced synthesis of one of the chains are called thalassemias. They can result from deletion of the gene for a chain or from a mutation in the regulatory gene that controls the synthesis of the chain.

The life cycle of red blood cells and the breakdown of hemoglobin. From Polaski and Tatro, 1996.hemoglobin A_1c hemoglobin A with a glucose group attached to the amino terminal of the beta chain; it is made at a slow constant rate during the 120-day life span of the erythrocyte. It accounts for 3 to 6 per cent of the total hemoglobin in a normal person and up to 12 per cent in persons with diabetes mellitus. Increased levels correlate with glucose intolerance in diabetics; with good diabetic control its level returns to normal range, so that periodic assays can be helpful in evaluating effective control of diabetes.glycated hemoglobin (glycosylated hemoglobin) any of various hemoglobins with glucose attached nonenzymatically; the most common one is hemoglobin A_1c. The percentage of hemoglobin that is glycosylated can be assessed over a long period of time as a gauge of blood sugar control; the normal range for a nondiabetic person is between 4 and 6 per cent.mean corpuscular hemoglobin (MCH) the average hemoglobin content of an erythrocyte, conventionally expressed in picograms per red cell, obtained by multiplying the blood hemoglobin concentration (in g/dl) by 10 and dividing by the red cell count (in millions per ml): MCH = Hb/RBC.

he·mo·glo·bin (Hb, Hgb),

(hē'mō-glō'bin), [MIM*141800-142310] The red respiratory protein of erythrocytes, consisting of approximately 3.8% heme and 96.2% globin, with a molecular weight of 64,450, which as oxyhemoglobin (HbO₂) transports oxygen from the lungs to the tissues where the oxygen is readily released and HbO₂ becomes Hb. When Hb is exposed to certain chemicals, its normal respiratory function is blocked; for example, the oxygen in HbO₂ is easily displaced by carbon monoxide, thereby resulting in the formation of fairly stable carboxyhemoglobin (HbCO), as in asphyxiation resulting from inhalation of exhaust fumes from gasoline engines. When the iron in Hb is oxidized from the ferrous to ferric state, as in poisoning with nitrates and certain other chemicals, a nonrespiratory compound, methemoglobin (MetHb), is formed.
In humans there are at least five kinds of normal Hb: two embryonic Hb's (Hb Gower-1, Hb Gower-2), fetal (Hb F), and two adult types (Hb A, Hb A₂). There are two α globin chains containing 141 amino acid residues, and two of another kind (β, γ, δ, ε, or ζ), each containing 146 amino acid residues in four of the Hb's. Hb Gower-1 has two ζ chains and two ε chains. The production of each kind of globin chain is controlled by a structural gene of similar Greek letter designation; normal individuals are homozygous for the normal allele at each locus. Substitution of one amino acid for another in the polypeptide chain can occur at any codon in any of the five loci and have resulted in the production of many hundreds of abnormal Hb types, most of no known clinical significance. In addition, deletions of one or more amino acid residues are known, as well as gene rearrangements due to unequal crossing over between homologous chromosomes.
The Hb types below are the main abnormal types known to be of clinical significance. Newly discovered abnormal Hb types are first assigned a name, usually the location where discovered, and a molecular formula is added when determined. The formula consists of Greek letters to designate the basic chains, with subscript 2 if there are two identical chains; a superscript letter (^A if normal for adult Hb, etc.) is added, or the superscript may designate the site of amino acid substitution (numbering amino acid residues from the N-terminus of the polypeptide) and specifying the change, using standard abbreviations for the amino acids. There is an exhaustive listing of variant Hb's in MIM in which a composite numbering system is used.

hemoglobin

(hē′mə-glō′bĭn)n. The protein in the red blood cells of vertebrates that carries oxygen from the lungs to tissues and that consists of four polypeptide subunits, each of which is bound to an iron-containing heme molecule.

hemoglobin

Hb Physiology A tetrameric 64 kD protein that is the major constituent of RBCs, which transports O₂, and buffers CO₂ produced by respiration; Hb transports O₂ and CO₂ and which comprises 99% of the protein weight of RBCs; it is composed of 2 α chains, each 141 amino acids in length, encoded from the zeta chain gene on chromosome 16 and 2 β chains, each 144 amino acids in length, encoded from the contiguous eta, Gγ, Aγ and delta chain genes on chromosome 11 Forms of Hb HbF is formed in the fetus and is the major Hb until birth; at birth up to 30% of the hemoglobin is HbA; most adult Hb is HbA with small amounts of HbF and HbA₂; Hb defects are inherited and termed hemoglobinopathies. See Carboxyhemoglobin, Chemically modified hemoglobin, Fetal hemoglobin, Reduced hemoglobin.

he·mo·glo·bin

(Hgb, Hb) (hē'mō-glō'bin) The red respiratory protein of erythrocytes, consisting of approximately 3.8% heme and 96.2% globin, with a molecular weight of 64,450, which as oxyhemoglobin (HbO₂) transports oxygen from the lungs to the tissues where the oxygen is readily released and HbO₂ becomes Hb. When Hb is exposed to certain chemicals, its normal respiratory function is blocked; thus, oxygen in HbO₂ is easily displaced by carbon monoxide, a process that results in the formation of fairly stable carboxyhemoglobin (HbCO), as in asphyxiation resulting from inhalation of exhaust fumes from gasoline engines. When the iron in Hb is oxidized from the ferrous to ferric state, as in poisoning with nitrates and certain other chemicals, a nonrespiratory compound, methemoglobin (MetHb), is formed.
Synonym(s): haemoglobin.

hemoglobin

(he'mo-glo?bin) [ hem- + globin],

Hb, Hbg, Hgb

The iron-containing pigment of red blood cells (RBCs) that carries oxygen from the lungs to the tissues. The amount of hemoglobin in the blood averages 12 to 16 g/100 ml in women, 14 to 18 g/100 ml in men, and somewhat less in children. Hemoglobin is a crystallizable, conjugated protein consisting of heme and globin. In the lungs, 1 g of hemoglobin combines readily with 1.36 cc of oxygen by oxygenation to form oxyhemoglobin. In the tissues where oxygen concentration is low and carbon dioxide (CO₂) concentration is high (low pH), hemoglobin releases its oxygen. Hemoglobin also acts as a buffer for the hydrogen ions produced in RBCs when (CO₂) is converted to bicarbonate ions for transport in the plasma.

When old RBCs are phagocytized by macrophages in the liver, spleen, and red bone marrow, the iron of hemoglobin is reused immediately to produce new RBCs or is stored in the liver until needed. The globin is converted to amino acids for the synthesis of other proteins. The heme portion is of no further use and is converted to bilirubin.

Hemoglobin combines with carbon monoxide (in carbon monoxide poisoning) to form the stable compound carboxyhemoglobin, which renders hemoglobin unable to bond with oxygen and results in hypoxia of tissues. Oxidation of the ferrous iron of hemoglobin to the ferric state produces methemoglobin.

Hundreds of different types of hemoglobin have been discovered. See: blood

HEMOGLOBIN A MOLECULE

hemoglobin A

A hemoglobin molecule composed of two alpha and two beta chains. See: illustration

hemoglobin A_1c

Abbreviation: Hb A_1c
Hemoglobin A that contains a glucose group linked to the terminal amino acid of the beta chains of the molecule. Levels of hemoglobin A_1c can be used to determine both the presence of diabetes mellitus (in previously undiagnosed patients) and the degree of glycemic control of known diabetics. The amount of glucose bound to the hemoglobin depends on the average concentration of glucose in the blood over time. In patients with diabetes mellitus, when the blood glucose level is optimally and carefully regulated over 8 to 12 weeks, the Hb A_1c level is normal or slightly elevated. If the blood glucose level has not been controlled (and has been abnormally elevated) in the preceding 8 to 12 weeks, the Hb A_1c blood level is increased. Hb A_1c is a good indicator of long-term glycemic control. The blood test for it may be performed when the patient is not fasting. Synonym: glycohemoglobin; glycated hemoglobin; glycosylated hemoglobin

Barts hemoglobin

See: Barts hemoglobin

hemoglobin C

A hemoglobin molecule in which lysine is substituted for glutamic acid at the sixth position of the beta chain. This substitution decreases the solubility of the hemoglobin molecule and increases the rigidity of the red blood cell membrane.

hemoglobin E

A hemoglobin molecule in which lysine is substituted for glutamic acid at the 26th position of the beta chain. This variation is found most often in those of Southeast Asian ancestry.

fetal hemoglobin

The type of hemoglobin found in the erythrocytes of the normal fetus. It has better oxygen-binding capacity than adult hemoglobin and is able to extract oxygen from the placenta to meet the needs of the fetus.

Patient care

The induction of fetal hemoglobin (with drugs such as hydroxyurea) in patients with sickle cell anemia often improves their clinical status because fetal hemoglobin does not deform or “sickle” in the circulation. It is capable of taking up and giving off oxygen at lower oxygen tensions than the hemoglobin in adult erythrocytes.

free plasma hemoglobin

Plasma hemoglobin.

glycated hemoglobin

Hemoglobin A_1c.

glycosylated hemoglobin

Hemoglobin A_1c.

hemoglobin Lepore

A variant hemoglobin formed by an unequal crossover and fusion of the beta and delta genes. A single copy of the variant gene causes thalassemia minor. Homozygotes have thalassemia intermedia.

mean cell hemoglobin

The hemoglobin content of the average RBC, usually expressed in picograms per red cell and calculated by multiplying the number of grams of hemoglobin/100 ml by 10 and dividing by the red cell count. Synonym: mean corpuscular hemoglobin

mean corpuscular hemoglobin

Abbreviation: MCH
Mean cell hemoglobin.

plasma hemoglobin

Hemoglobin released from red blood cells when they are destroyed (lyzed). It circulates in the blood and extravascular tissues. Synonym: free plasma hemoglobin

Hemoglobin (Hb)

An iron-containing pigment of red blood cells composed of four amino acid chains (alpha, beta, gamma, delta) that delivers oxygen from the lungs to the tissues of the body.Mentioned in: Anemias, Anoxia, Antianemia Drugs, Biliary Atresia, Blood Gas Analysis, Carbon Monoxide Poisoning, Coombs' Tests, Cyanosis, Erythroblastosis Fetalis, Haptoglobin Test, Hematocrit, Hemoglobin Test, Hemoglobinopathies, Iron Deficiency Anemia, Jaundice, Liposuction, Multiple Myeloma, Neonatal Jaundice, Platelet Function Disorders, Porphyrias, Sickle Cell Disease, Thalassemia, 2,3-Diphosphoglycerate Test

he·mo·glo·bin

(Hb) (hē'mō-glō'bin) [MIM*141800142310, MIM*141800] Red respiratory protein of erythrocytes. In humans, there are at least five kinds of normal Hb: two embryonic Hbs (Hb Gower-1, Hb Gower-2), fetal (Hb F), and two adult types (Hb A, Hb A₂).
Synonym(s): haemoglobin.

Patient discussion about Hemoglobin

Q. Can Jantoven cause hemoglobin to drop? A. Yes. In that case, you may consider consulting a doctor, since it may result from bleeding that may necessitate treatment.

Q. What is the Definition of Anemia? My doctor told me I have anemia, based on my latest blood tests. What is anemia?A. In laymans terms it is low iron. Most women get it sometime in their lives due to menstration and other factors. You need to increase your iron intake. Lots of beets, beans, spinich, and lots of other foods can help.

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REFERENCES

hemoglobin

haemoglobin

Hemoglobin

hemoglobin

he·mo·glo·bin (Hb, Hgb),

hemoglobin

hemoglobin

he·mo·glo·bin

hemoglobin

Hb, Hbg, Hgb

hemoglobin A

hemoglobin A1c

Barts hemoglobin

hemoglobin C

hemoglobin E

fetal hemoglobin

Patient care

free plasma hemoglobin

glycated hemoglobin

glycosylated hemoglobin

hemoglobin Lepore

mean cell hemoglobin

mean corpuscular hemoglobin

plasma hemoglobin

Hemoglobin (Hb)

he·mo·glo·bin

Patient discussion about Hemoglobin

hemoglobin

Synonyms for hemoglobin

noun a hemoprotein composed of globin and heme that gives red blood cells their characteristic color

Synonyms

Related Words

hemoglobin A_1c