title: Molecular stability of Hb Philly (alpha 2 beta 2 35(Cl) Tyr leads to Phe). Rhe relationship of hemoglobin stability to ligand state as defined by heat and mechanical shaking tests.
abstract: The molecular stability of Hb Philly (alpha 2 beta 2 35(Cl) Tyr leads to Phe) with different ligand states was compared with that of Hb A and Hb S using mechanical shaking and heat stability tests. The rates of mechanical denaturation of the oxy-forms of these hemoglobins decreased in the order of Hb S, Hb Philly, and Hb A, with relative ratios of 9.5: 5.6: 1.0. Upon oxidation to the met-forms, Hb Philly became mechanically most unstable, with ratios of 13.3: 23.0: 1.8, respectively. The deoxy-forms, of Hb A and Hb S were very stable, while that of Hb Philly was as unstable as the oxy-form. The addition of inositol hexaphosphate (IHP) to deoxy-Hb Philly stabilized the molecules. Since IHP restores the cooperative oxygen binding of Hp Philly, deoxy-Hb Philly appears to combine with IHP to change the quaternary structure required for cooperative oxygen binding and for stabilization of the molecule.
mesh_terms: D004355:Drug Stability; D004912:Erythrocytes / Q000032:analysis; D006441:Hemoglobin A; D006451:Hemoglobin, Sickle; D006455:Hemoglobins, Abnormal; D006358:Hot Temperature; D006801:Humans; D010108:Oxyhemoglobins; D010649:Phenylalanine; D011489:Protein Denaturation; D014443:Tyrosine
chemical_list: D006451:Hemoglobin, Sickle; D006455:Hemoglobins, Abnormal; D010108:Oxyhemoglobins; D014443:Tyrosine; D010649:Phenylalanine; C029519:hemoglobin Philly; D006441:Hemoglobin A