Effect of amino acid at the beta 6 position on surface hydrophobicity, stability, solubility, and the kinetics of polymerization of hemoglobin. Comparisons among Hb A (Glu beta 6), Hb C (Lys beta 6), Hb Machida (Gln beta 6), and Hb S (Val beta 6). 1987

K Adachi, and J Kim, and R Travitz, and T Harano, and T Asakura
Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania School of Medicine 19104.

Surface hydrophobicity, stability, solubility, and kinetics of polymerization were studied using hemoglobins with four different amino acids at the beta 6 position: Hb A (Glu beta 6), Hb C (Lys beta 6), Hb Machida (Gln beta 6), and Hb S (Val beta 6). The surface hydrophobicity increased in the order of Hb C, Hb A, Hb Machida, and Hb S, coinciding with the hydrophobicity of the amino acid at the beta 6 position. Solubility of the oxy-form of these hemoglobins decreased in relation to increases in their surface hydrophobicity, suggesting that the solubility is controlled by the strength of hydrophobicity of the amino acid at the beta 6 position. The solubility of the oxy-form of these hemoglobins is always higher than that of the deoxy-form. There is a similar linear relationship between the solubility and surface hydrophobicity among deoxyhemoglobins A, C, and Machida. However, the solubility of deoxy-Hb S deviated significantly from the expected value, indicating that the extremely low solubility of deoxy-Hb S is not directly related to the hydrophobicity of the beta 6 valine. Kinetic studies on the polymerization of deoxy-Hb Machida revealed a distinct delay time prior to polymerization. This confirms our previous hypothesis that beta 6 valine is not responsible for the delay time prior to gelation. The kinetics of the polymerization of 1:1 mixtures of sickle and non-sickle hemoglobins were similar to those of pure Hb S, suggesting that only one of the two beta 6 valines is involved in an intermolecular contact. In mixtures of equal amounts of Hb S and Hb A, Hb C, or Hb Machida, half of the asymmetrical AS, SC, and S-Machida hybrid hemoglobins behaved like Hb S during nucleation, while the other half behaved like the non-sickle hemoglobin.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008239 Lysine An essential amino acid. It is often added to animal feed. Enisyl,L-Lysine,Lysine Acetate,Lysine Hydrochloride,Acetate, Lysine,L Lysine
D010108 Oxyhemoglobins A compound formed by the combination of hemoglobin and oxygen. It is a complex in which the oxygen is bound directly to the iron without causing a change from the ferrous to the ferric state. Oxycobalt Hemoglobin,Oxycobalthemoglobin,Oxyhemoglobin,Hemoglobin, Oxycobalt
D004355 Drug Stability The chemical and physical integrity of a pharmaceutical product. Drug Shelf Life,Drugs Shelf Lives,Shelf Life, Drugs,Drug Stabilities,Drugs Shelf Life,Drugs Shelf Live,Life, Drugs Shelf,Shelf Life, Drug,Shelf Live, Drugs,Shelf Lives, Drugs
D005971 Glutamates Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure. Glutamic Acid Derivatives,Glutamic Acids,Glutaminic Acids
D005973 Glutamine A non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from GLUTAMIC ACID and AMMONIA. It is the principal carrier of NITROGEN in the body and is an important energy source for many cells. D-Glutamine,L-Glutamine,D Glutamine,L Glutamine
D006441 Hemoglobin A Normal adult human hemoglobin. The globin moiety consists of two alpha and two beta chains.
D006444 Hemoglobin C A commonly occurring abnormal hemoglobin in which lysine replaces a glutamic acid residue at the sixth position of the beta chains. It results in reduced plasticity of erythrocytes.
D006451 Hemoglobin, Sickle An abnormal hemoglobin resulting from the substitution of valine for glutamic acid at position 6 of the beta chain of the globin moiety. The heterozygous state results in sickle cell trait, the homozygous in sickle cell anemia. Hemoglobin S,Deoxygenated Sickle Hemoglobin,Deoxyhemoglobin S,Hemoglobin SS,Hemoglobin, Deoxygenated Sickle,SS, Hemoglobin,Sickle Hemoglobin,Sickle Hemoglobin, Deoxygenated
D006454 Hemoglobins The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements. Eryhem,Ferrous Hemoglobin,Hemoglobin,Hemoglobin, Ferrous

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