title: Unfolding and release of heme from human hemoglobins A, S and F.
abstract: 1. Analysis of the Soret spectra of hemoglobins A, S and F has been used to determine the extent of heme exposure and release from these hemoglobins in the presence of several solvent perturbants. 2. Oxyhemoglobin S unfolding in the presence of either urea or propyl urea resulted in greater heme exposure and release than either oxyhemoglobins A or F. 3. Methemoglobin formation resulted in lower denaturation midpoints for each hemoglobin compared to the reduced oxyhemoglobin state; methemoglobin F had the lowest denaturation midpoint under isothermal denaturing conditions. 4. Rate of heme exposure was greater for oxyhemoglobin S than oxyhemoglobin A in the presence of 200 microM the anionic detergent sodium dodecyl sulfate. 5. Evidence for increased levels of heme release in hemoglobin S may be related to the greater tendency of sickled red cell membranes to undergo lipid oxidation.
authors.affiliation: Department of Chemistry and Comprehensive Sickle Cell Center, University of South Alabama, Mobile 36688.
authors.forename: J P
authors.initials: JP
authors.lastname: Harrington
authors.forename: L
authors.initials: L
authors.lastname: Keaton
mesh_terms: D005319:Fetal Hemoglobin / Q000737:chemistry*; D006418:Heme / Q000737:chemistry*; D006441:Hemoglobin A / Q000737:chemistry*; D006451:Hemoglobin, Sickle / Q000737:chemistry*; D006801:Humans; D008706:Methemoglobin / Q000737:chemistry; D010084:Oxidation-Reduction; D010108:Oxyhemoglobins / Q000737:chemistry; D011489:Protein Denaturation; D017510:Protein Folding; D014508:Urea / Q000031:analogs & derivatives
chemical_list: D006451:Hemoglobin, Sickle; D010108:Oxyhemoglobins; C017680:propylurea; C029775:oxyhemoglobin S; D006418:Heme; D014508:Urea; D008706:Methemoglobin; D006441:Hemoglobin A; D005319:Fetal Hemoglobin; C029774:oxyhemoglobin A