The only one of the six contenders that includes genetically modified ingredients, the Impossible Burger contains a compound (soy leghemoglobin) created and manufactured by the company from plant hemoglobins; it quite successfully replicates the "bloody" look and taste of a rare burger.
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These hemoglobins also carry sulfides normally fatal in other animals.
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Vertebrate hemoglobins are tetrameric molecules comprised of two distinct polypeptide chains.
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This saves time, because beta hemoglobins have been sequenced for innumerable organisms.
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Since then, more than 200 variant and abnormal hemoglobins have been described.
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Reporting variant hemoglobins discovered during hemoglobin A1c analysis common practices in clinical laboratories.
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From the FDA's point of view, however, modified hemoglobins may be farther along.
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Two current areas of research promise to enhance developmental studies on cladoceran hemoglobins, however.
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A clear example are genes coding for haemoglobin subunits. These genes are easily duplicated and lost. As a consequence, there are huge differences regarding the number and relative position of the genes of alpha-hemoglobins and beta- hemoglobins in mammals. In birds, that is not the case.
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Work by Arredondo-Peter, Vinogradov and collaborators has elucidated the major events that could have occurred during the evolution of Phytogbs.Vázquez-Limón C., Hoogewijs D., Vinogradov S. N.,Arredondo-Peter R., The evolution of land plant hemoglobins, Plant Sci., 191-192 (2012) 71-81.Vinogradov S. N., Fernández I., Hoogewijs D.,Arredondo-Peter R., Phylogenetic relationships of 3/3 and 2/2 hemoglobins in Archaeplastida genomes to bacterial and other eukaryote hemoglobins, Mol. Plant, 4 (2011) 42-58.
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Molecular dynamics analysis of a second phosphate site in the hemoglobins of the seabird, south polar skua.
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Early findings lead Asakura to predict that researchers may create novel hemoglobins capable of super-efficient oxygen delivery.
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In general on alkaline electrophoresis in order of increasing mobility are hemoglobins A2, E=O=C, G=D=S=Lepore, F, A, K, J, Bart's, N, I, and H. In general a sickling test (sodium bisulfite) is performed on abnormal hemoglobins migrating in the S location to see if the red cells precipitate in solution.
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One of the two vascular hemoglobins possesses a hexagonal-bilayer hemoglobin quaternary structure, which is only found in the Annelida and Vestimentifera.
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They are purified cellfree hemoglobins, where the globin portion of the molecule has been modified chemically by conjugation, cross-linking or polymerizing.
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The worms' upper end is a deep-red fan-like structure ("plume"), which extends into the water and absorbs H2S and O2 for the bacteria, and CO2 for use as synthetic raw material similar to photosynthetic plants. The structures are bright red due to their content of several extraordinarily complex hemoglobins that have up to 144 globin chains, each including associated heme structures. These hemoglobins are remarkable for being able to carry oxygen in the presence of sulfide, and even to carry sulfide, without being completely "poisoned" or inhibited by it as hemoglobins in most other species are.
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The giant tube worm Riftia pachyptila showing red hemoglobin-containing plumes The structure of hemoglobins varies across species. Hemoglobin occurs in all kingdoms of organisms, but not in all organisms. Primitive species such as bacteria, protozoa, algae, and plants often have single-globin hemoglobins. Many nematode worms, molluscs, and crustaceans contain very large multisubunit molecules, much larger than those in vertebrates.
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Vinogradov S. N., Hoogewijs D.,Arredondo-Peter R., What are the origins and phylogeny of plant hemoglobins?, Commun. Integrat. Biol., 4 (2011) 443-445.
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The global impact may be substantially larger because variant hemoglobins are reportedly present in up to one-third of all diabetic individuals in other parts of the world.
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The mechanisms by which erythrocytes containing abnormal hemoglobins, or are G6PD deficient, are partially protected against P. falciparum infections are not fully understood, although there has been no shortage of suggestions. During the peripheral blood stage of replication malaria parasites have a high rate of oxygen consumption and ingest large amounts of hemoglobin. It is likely that HbS in endocytic vesicles is deoxygenated, polymerizes and is poorly digested. In red cells containing abnormal hemoglobins, or which are G6PD deficient, oxygen radicals are produced, and malaria parasites induce additional oxidative stress.
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The species is named for Unni E. H. Fyhn, a postdoctoral student in the laboratory of the author in the 1970s who continued to work on the genetic control of fish hemoglobins until her untimely death from cancer.
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Following the 1949 paper, Itano left the Pauling laboratory to work with Neel; in the following years Itano and Neel used electrophoresis to identify a number of other human hemoglobin variants, including some associated with other diseases. At Caltech, a comparison of the amino acid content of normal and sickle cell hemoglobins showed that there were several differences in chemical makeup, but did not explain the difference in electric charge that made electrophoretic separation possible. The cause of this difference was pinpointed in 1956 and 1957, when Vernon Ingram used protein fingerprinting (a combination of electrophoresis and chromatography) to show that the key difference between normal hemoglobins and sickle cell hemoglobins was a single difference in one chain of the protein: a glutamic acid residue on the normal hemoglobin in place of a valine residue on the sickle cell hemoglobin. The molecular disease concept put forward in the 1949 paper also became the basis for Linus Pauling's view of evolution.
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He retired from that position in 1987. His hematology research included important work on blood coagulation, blood platelets, hemorrhagic diseases, and hemoglobins. He made significant contributions to developing a therapy for vitamin B-12 deficiency. In 1947 he discovered and described lupus anticoagulants.
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Hydrothermal vent tubeworms get organic compounds from bacteria that live in their trophosome. Isolating the vermiform body from white chitonous tube, a small difference exists from the classic three subdivisions typical of phylum Pogonophora: the prosoma, the mesosoma, and the metasoma. R. pachyptila community with extroflexion of red branchial plume The first body region is the vascularized branchial plume, which is bright red due to the presence of hemoglobin that contain up to 144 globin chains (each presumably including associated heme structures). These tube worm hemoglobins are remarkable for carrying oxygen in the presence of sulfide, without being inhibited by this molecule, as hemoglobins in most other species are.
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The first line of defense against malaria is mainly exerted by abnormal hemoglobins and glucose-6-phosphate dehydrogenase deficiency. The three major types of inherited genetic resistance – sickle cell disease, thalassemias, and G6PD deficiency – were present in the Mediterranean world by the time of the Roman Empire.
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What they found was that the rates were not the same among proteins. Each protein has its own rate, and that rate is constant across phylogenies (i.e., hemoglobin does not evolve at the same rate as cytochrome c, but hemoglobins from humans, mice, etc. do have comparable rates of evolution.).
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New York:BasicBooks, 1995. p. 90 After failing with a number of other techniques, Itano succeeded in differentiating normal and sickle cell hemoglobins using moving boundary electrophoresis."The Register of Harvey Itano Papers 1946 - 2000 ", MSS 0226, Mandeville Special Collections Library, Geisel Library, University of California, San Diego. Accessed August 25, 2008.
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Detects different Haemoglobin types Hemoglobin electrophoresis is a blood test that can detect different types of hemoglobin. It uses the principles of gel electrophoresis to separate out the various types of hemoglobin and is a type of native gel electrophoresis. The test can detect abnormal levels of HbS, the form associated with sickle-cell disease, as well as other abnormal hemoglobin-related blood disorders, such as beta thalassemia and hemoglobin C. It can also be used to determine whether there is a deficiency of any normal form of hemoglobin, as in the group of diseases known as thalassemias. Different hemoglobins have different charges, and according to those charges and the amount, hemoglobins move at different speeds in the gel whether in alkaline gel or acid gel.
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Analyzers may count nucleated red blood cells, giant and clumped platelets, and red blood cells containing abnormal hemoglobins (such as Hemoglobin S in sickle cell disease) as white blood cells, leading to faulty differential results. Automated differential counts on aged specimens may be incorrect due to cellular degeneration.Keohane, E et al. (2015). p. 226.
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Hardison R. C., A brief history of hemoglobins: plant, animal, protist, and bacteria., Proc. Natl. Acad. Sci. USA., 93 (1996) 5675-5679 The existence of a second intron in the phytogb genes was predicted by Go using theoretical analysis,Go M., Correlation of DNA exonic regions with protein structural units in haemoglobin., Nature, 291 (1981) 90-92.
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The best known hemoglobinopathy is sickle-cell disease, which was the first human disease whose mechanism was understood at the molecular level. A (mostly) separate set of diseases called thalassemias involves underproduction of normal and sometimes abnormal hemoglobins, through problems and mutations in globin gene regulation. All these diseases produce anemia. 300x300px Variations in hemoglobin amino acid sequences, as with other proteins, may be adaptive.
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Heinz bodies (also referred to as "Heinz-Ehrlich bodies") are inclusions within red blood cells composed of denatured hemoglobin."Unstable Hemoglobins: The Role of Heme Loss in Heinz Body Formation" Jacon, Harry and Winterhalter, Kaspar, Proceedings of the National Academy of Sciences, Vol. 64, No3, pp. 697-701, March 1970 They are not visible with routine blood staining techniques, but can be seen with supravital staining.
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This results in the Hb-O2 dissociation curve being shifted downward and not just to the right. At low pH, hemoglobins showing the Root effect don't become fully oxygenated even at oxygen tensions up to 20kPa. This effect allows hemoglobin in fish with swim bladders to unload oxygen into the swim bladder against a high oxygen gradient.Verde, C., A. Vergara, D. Giordano, L. Mazzarella, and G. di Prisco. 2007.
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The simplest carbohydrate is glucose, CHO, is used in cellular respiration to produce ATP, adenosine triphosphate, which supplies cells with energy. Proteins are chains of amino acids that function , among other things, to contract skeletal muscle, as catalysts, as transport molecules, and as storage molecules. Protein catalysts can facilitate biochemical processes by lowering the activation energy of a reaction. Hemoglobins are also proteins, carrying oxygen to an organism's cells.
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The soluble hemoglobins, present in the tentacles, are able to bind O2 and H2S, which are necessary for chemosynthetic bacteria. Due to the capillaries, these compounds are absorbed by bacteria. During the chemosynthesis, the mitochondrial enzyme rhodanase catalyzes the disproportionation reaction of the thiosulfate anion S2O32- to sulfur S and sulfite SO32- . The R. pachyptila’s bloodstream is responsible for absorption of the O2 and nutrients such as carbohydrates.
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The Root effect is a physiological phenomenon that occurs in fish hemoglobin, named after its discoverer R. W. Root. It is the phenomenon where an increased proton or carbon dioxide concentration (lower pH) lowers hemoglobin's affinity and carrying capacity for oxygen. The Root effect is to be distinguished from the Bohr effect where only the affinity to oxygen is reduced. Hemoglobins showing the Root effect show a loss of cooperativity at low pH.
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Wu's results confirmed Maurice Pryce and John Clive Ward's calculations on the correlation of the quantum polarizations of two photons propagating in opposite directions. Wu later conducted research into the molecular changes in the deformation of hemoglobins that cause sickle-cell disease. She also did research on magnetism and the Mössbauer effect during the 1960s. She wrote a textbook with , Beta Decay, which was published in 1966 and became a standard reference on the subject.
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If a plastic blood gas syringe is used, the sample should be transported and kept at room temperature and analyzed within 30 min. If prolonged time delays are expected (i.e., greater than 30 min) prior to analysis, the sample should be drawn in a glass syringe and immediately placed on ice. Standard blood tests can also be performed on arterial blood, such as measuring glucose, lactate, hemoglobins, dys-haemoglobins, bilirubin and electrolytes.
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The free heme can then accelerate tissue damage by promoting peroxidative reactions and activation of inflammatory cascades. Hemopexin (Hx) is another plasma glycoprotein able to bind heme with high affinity. Hx sequesters heme in an inert, non-toxic form and transports it to the liver for catabolism and excretion. As long as both haptoglobin and hemopexin are saturated, the remaining free hemoglobins are filtered in the kidney and some of them will be reabsorbed by way of proximal tubules.
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In these tissues, hemoglobin has a non-oxygen-carrying function as an antioxidant and a regulator of iron metabolism. Excessive glucose in one's blood can attach to hemoglobin and raise the level of hemoglobin A1c. Hemoglobin and hemoglobin-like molecules are also found in many invertebrates, fungi, and plants. In these organisms, hemoglobins may carry oxygen, or they may act to transport and regulate other small molecules and ions such as carbon dioxide, nitric oxide, hydrogen sulfide and sulfide.
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The amino acid sequences of the globin proteins in hemoglobins usually differ between species. These differences grow with evolutionary distance between species. For example, the most common hemoglobin sequences in humans, bonobos and chimpanzees are completely identical, without even single amino acid difference in either the alpha or the beta globin protein chains. Whereas the human and gorilla hemoglobin differ in one amino acid in both alpha and beta chains, these differences grow larger between less closely related species.
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Bite cells are caused by G6PD deficiency, NADPH deficiency, thalassemia, glutathione synthase deficiency, and other red-cell enzymopathies involving the pentose phosphate shunt, oxidative drugs and unstable hemoglobins. People receiving large quantities of oxidative drugs such as dapsone or sulfasalazine are more prone to have degmacytes. The underlying cause of degmacytes is a result of the splenic macrophages removing Heinz bodies from the membrane of red blood cells, which results in a "bitten" appearance of the cell.
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Watts R. A., Hunt P. W., Hvitved A. N., Hargrove M. S., Peacock W. J.,Dennis E. S., A hemoglobin from plants homologous to truncated hemoglobins of microorganisms., Proc. Natl. Acad. Sci. USA., 98 (2001) 10119-10124. However, concentrations of Phytogbs increase in plants subjected to specific stress conditions, such as floodingTaylor E. R., Nie X. Z., MacGregor A. W.,Hill R. D., A cereal haemoglobin gene is expressed in seed and root tissues under anaerobic conditions, Plant Mol. Biol.
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In return, the plant supplies the bacteria with carbohydrates in the form of organic acids. The plant also provides the bacteroid oxygen for cellular respiration, tightly bound by leghaemoglobins, plant proteins similar to human hemoglobins. This process keeps the nodule oxygen poor in order to prevent the inhibition of nitrogenase activity. Recently, a Bradyrhizobium strain was discovered to form nodules in Aeschynomene without producing nod factors, suggesting the existence of alternative communication signals other than nod factors, possibly involving the secretion of the plant hormone cytokinin.
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Working with Dan Campbell at Caltech (within the Division of Chemistry headed by Linus Pauling), Goodman worked on the immunological properties of hemoglobins, including the immunological differences between normal and sickle-cell hemoglobin. According to a 2004 interview, Goodman became interested in evolutionary problems around 1957–1958. After research stints at the University of Illinois Medical School and the Detroit Institute of Cancer Research, he embarked--with his friend Morris Wilson--on studies of the degree of variability in proteins expressed early vs. late in development.
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Cytolysin refers to the substance secreted by microorganisms, plants or animals that is specifically toxic to individual cells,Computer Retrieval of Information on Scientific Projects (CRISP) - Thesaurus - Cytolysin "Cytolysin" entry from the American Heritage Medical Dictionary, on TheFreeDictionary.com (Retrieved on January 22, 2009) in many cases causing their dissolution through lysis. Cytolysins that have a specific action for certain cells are named accordingly. For instance, the cytolysins responsible for the destruction of red blood cells, thereby liberating hemoglobins, are named hemolysins, and so on.
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Phytoglobins (abbreviated as Phytogbs) are ubiquitously distributed in plants as they have been identified in algae and land plants, including primitive bryophytes and evolved monocots and dicots. They are classified as Phytogbs0, Phytogbs1 and Phytogbs2 (formerly known as non-symbiotic hemoglobins), symbiotic Phytogbs, leghemoglobins (abbreviated as Lbs) and Phytogbs3.Hill R., Hargrove M. S.,Arredondo-Peter R., Phytoglobin: a novel nomenclature for plant globins accepted by the globin community at the 2014 XVIII conference on Oxygen- Binding and Sensing Proteins., F1000Research, 5 (2016) 212 (doi: 210.12688/f11000research.18133.12681).
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The cycle involving nitrate reductase, reduction of nitrite to NO, scavenging NO by phytoglobin was defined as the phytoglobin-NO cycle. Its operation leads to the maintenance of redox and energy status during hypoxia and results in the reduced production of ethanol and lactic acid. Phytogbs0, 1, 2 and 3 are synthesized at very low concentrations in diverse (embryonic and vegetative) plant organs.Garrocho- Villegas V.,Arredondo-Peter R., Molecular cloning and characterization of a moss (Ceratodon purpureus) non-symbiotic hemoglobin provides insight into the early evolution of plant non-symbiotic hemoglobins.
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Max Perutz won the Nobel Prize for chemistry for his work determining the molecular structure of hemoglobin and myoglobin"Max Perutz, Father of Molecular Biology, Dies at 87 ". The New York Times. February 8, 2002 In 1825 J. F. Engelhart discovered that the ratio of iron to protein is identical in the hemoglobins of several species. From the known atomic mass of iron he calculated the molecular mass of hemoglobin to n × 16000 (n = number of iron atoms per hemoglobin, now known to be 4), the first determination of a protein's molecular mass.
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In particular, chimeric hemoglobins found in fungi and giant annelids may contain both globin and other types of proteins. One of the most striking occurrences and uses of hemoglobin in organisms is in the giant tube worm (Riftia pachyptila, also called Vestimentifera), which can reach 2.4 meters length and populates ocean volcanic vents. Instead of a digestive tract, these worms contain a population of bacteria constituting half the organism's weight. The bacteria oxidize H2S from the vent with O2 from the water to produce energy to make food from H2O and CO2.
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As a result, Hox genes in most vertebrates are clustered across multiple chromosomes with the HoxA-D clusters being the best studied. Another example are the globin genes which encode myoglobin and hemoglobin and are considered to be ancient paralogs. Similarly, the four known classes of hemoglobins (hemoglobin A, hemoglobin A2, hemoglobin B, and hemoglobin F) are paralogs of each other. While each of these proteins serves the same basic function of oxygen transport, they have already diverged slightly in function: fetal hemoglobin (hemoglobin F) has a higher affinity for oxygen than adult hemoglobin.
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Acta – Bioenerget. 1606: 117–125 plant adaptation to hypoxic stress,Igamberdiev, A.U., Hill, R.D. (2004) Nitrate, NO and haemoglobin in plant adaptation to hypoxia: An alternative to classic fermentation pathways. J. Exp. Bot. 55: 2473–2482 nitric oxide metabolism in plants and the role of plant hemoglobins,Igamberdiev, A.U., Bykova, N.V., Hill, R.D. (2006) Scavenging of nitric oxide by barley hemoglobin is facilitated by a monodehydroascorbate reductase-mediated ascorbate reduction of methemoglobin. Planta 223: 1033–1040 foundations of theoretical biology,Igamberdiev, A.U. (2007) Physical limits of computation and emergence of life.
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Sickle cells in human blood: both normal red blood cells and sickle-shaped cells are present Any condition that results in the production of abnormal hemoglobin is included under the broad category of hemoglobinopathies. Worldwide, it is estimated that 7% of the population may carry a hemoglobinopathy with clinical significance. The most well known condition in this group is sickle cell disease. Newborn screening for a large number of hemoglobinopathies is done by detecting abnormal patterns using isoelectric focusing, which can detect many different types of abnormal hemoglobins.
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Hemocyanin (blue) contains copper and is found in crustaceans and mollusks. It is thought that tunicates (sea squirts) might use vanabins (proteins containing vanadium) for respiratory pigment (bright-green, blue, or orange). In many invertebrates, these oxygen- carrying proteins are freely soluble in the blood; in vertebrates they are contained in specialized red blood cells, allowing for a higher concentration of respiratory pigments without increasing viscosity or damaging blood filtering organs like the kidneys. Giant tube worms have unusual hemoglobins that allow them to live in extraordinary environments.
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The epsilon globin gene (HBE) is normally expressed in the embryonic yolk sac: two epsilon chains together with two zeta chains (an alpha-like globin) constitute the embryonic hemoglobin Hb Gower I; two epsilon chains together with two alpha chains form the embryonic Hb Gower II. Both of these embryonic hemoglobins are normally supplanted by fetal, and later, adult hemoglobin. The five beta-like globin genes are found within a 45 kb cluster on chromosome 11 in the following order: 5' - epsilon – gamma-G – gamma-A – delta – beta - 3'.
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Hemoglobin c (abbreviated as HbC) is an abnormal hemoglobin in which glutamic acid residue at the 6th position of the β-globin chain is replaced with a lysine residue due to a point mutation in the HBB gene. It produces sickle cell trait but not the disease, as it causes only mild sickling of the RBCs. Thus, it is the least dangerous among sickle cell trait-producing hemoglobins such as HbS and HbO. HbC was discovered by Harvey Itano and James V. Neel in 1950 from two African-American families.
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While all sabellids and serpulids employ chlorocruorin as an oxygen transport macromolecule, Serpula is the only genus that appears to possess both hemoglobin as well as chlorocruorin. Chlorocruorin is an oxygen-binding hemeprotein whose affinity for oxygen is weaker than that of most hemoglobins. A dichromatic compound, chlorocruorin is noted for appearing green in dilute solutions, though it appears light red when found in concentrated solutions. Its structure is very similar to erythrocruorin, each molecule being composed of more than a hundred interlinked 16-17kDa myoglobin-like subunits arranged in a giant complex with a total weight exceeding 3600kDa.
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Heme-Fe coordination is essential for Phytogb (and other globins) function because it regulates the rate of ligand-binding and –releasing as consequence of the kinetic constants kon and koff, respectively. For example, the affinity of soybean Lb and rice Phytogb1 for O2 (KO2) is moderate and very high because kon is 130 and 68 mM−1 s−1, koff is 5.6 and 0.038 s−1 and KO2 (i.e. the O2-affinity resulting from kon/koff) is 23 and 1800 mM−1, respectively.Arredondo-Peter R., Hargrove M. S., Moran J. F., Sarath G.,Klucas R. V., Plant hemoglobins, Plant Physiol.
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A variety of oxygen-transport and -binding proteins exist in organisms throughout the animal and plant kingdoms. Organisms including bacteria, protozoans, and fungi all have hemoglobin-like proteins whose known and predicted roles include the reversible binding of gaseous ligands. Since many of these proteins contain globins and the heme moiety (iron in a flat porphyrin support), they are often called hemoglobins, even if their overall tertiary structure is very different from that of vertebrate hemoglobin. In particular, the distinction of "myoglobin" and hemoglobin in lower animals is often impossible, because some of these organisms do not contain muscles.
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K. Bradford & H. Nonogaki (Eds.), Seed Development, Dormancy and Germination (Vol. 27, p. 164). Oxford, UK: Blackwell Publishing. In addition, although the function is unclear, a certain class of hemoglobins is present in the outer layer of living cells including the aleurone tissue in barley and rice seeds.(2007). K. Bradford & H. Nonogaki (Eds.), Seed Development, Dormancy and Germination (Vol. 27, p. 165). Oxford, UK: Blackwell Publishing. During seed germination, the plant embryo produces the hormone gibberellin which triggers the aleurone cells to release α-amylase for the hydrolysis of starch, proteases, and storage proteins into the endosperm.
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Chlorocruorin. Chlorocruorin is an oxygen-binding hemeprotein present in the blood plasma of many annelids, particularly certain marine polychaetes. Its affinity for oxygen is weaker than that of most hemoglobins. A dichromatic compound, chlorocruorin is noted for appearing green in dilute solutions, though it appears light red when found in concentrated solutions. Its structure is very similar to erythrocruorin (which is likewise very similar to multiple subunits of myoglobin) and it contains many 16-17 kDa myoglobin-like subunits arranged in a giant complex of over a hundred subunits with interlinking proteins as well with a total weight exceeding 3600 kDa.
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NODs, as well as many hemoglobins that function as NODs, are distributed to most life forms including bacteria, fungi, protists, worms, plants and animals. In fact, nitric oxide dioxygenation appears to be a primal function for members of the hemoglobin superfamily. Moreover, it is becoming increasingly evident that the NOD function of globins is much more common than the paradigmatic O2 transport-storage function of red cell hemoglobin which was first investigated and reported over a century earlier by Felix Hoppe-Seyler and others. Other proteins that may act as NODs include mammalian microsomal cytochrome P450(s) and a novel O2-binding cytochrome b from Rhodobacter sphaeroides.
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GATA1 was first described as a transcription factor that activates the hemoglobin B gene in the red blood cell precursors of chickens. Subsequent studies in mice and isolated human cells found that GATA1 stimulates the expression of genes that promote the maturation of precursor cells (e.g. erythroblasts) to red blood cells while silencing genes that cause these precursors to proliferate and thereby to self-renew. GATA1 stimulates this maturation by, for example, inducing the expression of genes in erythroid cells that contribute to the formation of their cytoskeleton and that make enzymes necessary for the biosynthesis of hemoglobins and heme, the oxygen-carrying components of red blood cells.
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After he finished his studies there, he was appointed as junior assistant in physiology of domestic animals at the Faculty of Agriculture and Food in Skopje."EXPERIENCE" In 1960, he specialized with a Master of Science in physiology and biochemistry at the University of Belgrade with help from his mentor, Professor Bozidar Nikolic. After his master's studies, Efremov defended his doctoral thesis, titled "Fetal and Adult Animal Hemoglobins," in September 1963 at the University of Belgrade. After his Ph.D. dissertation he began work as a professor at the Department of Internal Medicine, Veterinary College of Norway in Oslo, which was headed by Professor Mikael Braed.
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Photomicrograph of normal- shaped and sickle-shape red blood cells from a patient with sickle cell disease Sickle cell anemia is a genetic disease that causes deformed red blood cells with a rigid, crescent shape instead of the normal flexible, round shape. It is caused by a change in one nucleotide, a point mutation in the HBB gene. The HBB gene encodes information to make the beta-globin subunit of hemoglobin, which is the protein red blood cells use to carry oxygen throughout the body. Sickle cell anemia occurs when the HBB gene mutation causes both beta-globin subunits of hemoglobin to change into hemoglobinS (HbS).
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An alternative mechanism to preserve O2 delivery in the face of low ambient oxygen is to increase the affinity of the blood. The oxygen content of the blood is related to PaO2 and is illustrated using an oxygen equilibrium curve (OEC). Fish hemoglobins, with the exception of the agnathans, are tetramers that exhibit cooperativity of O2 binding and have sigmoidal OECs. Oxygen equilibrium curve (OEC) demonstrating the PO2 required for half of the hemoglobin oxygen binding sites to be saturated with oxygen (P50) The binding affinity of hemoglobin to oxygen is estimated using a measurement called P50 (the partial pressure of oxygen at which hemoglobin is 50% bound with oxygen) and can be extremely variable.
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James Lynn Hoard (December 28, 1905 – April 10, 1993) was an American chemist, a member of the Manhattan Project. New York Times:James Lynn Hoard, 87, Is Dead; Chemist Worked on Atom Bomb,By WOLFGANG SAXON, April 17, 1993 National Academies Press:Biographical Memoirs:James Lynn Hoard,By Robert E. Hughes Cornell University Library:Ecommons:James Lynn Hoard Hoard was internationally recognized for his research of boron. Linus Pauling, a Nobel Prize laureate, said that Hoard "contributed significantly to ... the chemistry of certain elements such as boron, and the structure of regions of hemoglobins where oxygen molecules are bonded to iron." Hoard was also notable for his work on the Manhattan project where he overcame some important challenges with the uranium compounds.
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Examining the hemoglobins of microbes and the parasitic worm Ascaris, Stamler found that these ancient forms of hemoglobin either eliminate NO enzymatically (bacteria and yeast) or utilize it to eliminate oxygen from its anaerobic environment (Ascaris), showing that the primordial function of hemoglobin was in NO processing not oxygen transport. Stamler also identified trans-kingdom SNO signaling (operating between species as a general language between microbiota and animal host), since microbiota that produce NO can lead to widespread protein S-nitrosylation in a Caenorhabditis elegans host with profound genetic and physiological consequences. Stamler also identified an enzymatic mechanism of nitroglycerin bioactivation to produce NO bioactivity, thus solving a longstanding mystery (i.e., the generation of NO from nitroglycerin was awarded a nobel prize in 1998, but how was not understood) and he demonstrated how nitroglycerin tolerance develops during therapy.
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His major work included the demonstration that free hemoglobin in the circulating plasma is excreted by the kidney owing to the dissociation of the a2b2 tetramer into ab dimers, discovery of the hemoglobin binding site of the physiologically important modifier 2,3 bisphosphoglycerate, demonstration that surface charge determines the proportion of commonly encountered mutant hemoglobins in heterozygotes, discovery of the first example of a hemoglobin frame shift mutation, establishment of sequence dependent rules for the cleavage of the initiator methionine and N-acetylation, demonstration with Paul Gallop that the minor hemoglobin component HbA1c contains glucose attached to the N-terminus of the beta globin chain by a ketosamine linkage, providing the rationale for the measurement of HbA1c as an index of long-term control in diabetics with later work indicating that this glucose dependent modification is a likely contributor to the long-term complications of diabetes.The second 20 years of Bunn's research focused on identification of domains on erythropoietin (EPO) that bind to its receptor, and on characterization of the oxygen-dependent degradation domain of the HIFa transcription factor responsible for hypoxic induction of EPO and other physiologically relevant proteins.
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