| Hemoglobin autoxidation under high oxygen pressure - effect of inositol hexaphosphate. | |
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MedLine Citation:
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PMID: 7319827 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Hemoglobin A in 0.05 M bis-tris buffer was autoxidized under various oxygen pressures from 0.21 (oxygen pressure in air) to 8 atmospheres at pHs 6.5 and 8.5. All experiments were carried out without and with 5 molar excess of inositol hexaphosphate/heme at 37 degrees C. It is shown that increasing the oxygen pressure from 0.21 to 1 atmosphere decreases the autoxidation rate to about 80% whereas increasing the oxygen pressure further to 8 atmospheres has a reverse effect. This phenomenon is observed at both acid and alkaline pHs, although it is less marked at the latter pH. The stimulating effect of inositol hexaphosphate on the autoxidation is abolished at high oxygen pressure. It is suggested that moderate elevation of the oxygen pressure above the atmospheric pressure stabilizes further the hemoglobin R conformation which decreases the autoxidation rate. At very high oxygen pressure, the oxidizing potential of oxygen oxidizes the oxyhemoglobin directly in the R conformation. The maximal shift of hemoglobin T in equilibrium with R conformational equilibrium towards R conformation interferes with the binding of inositol hexaphosphate and hence abolishes its effect. |
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Authors:
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A Mansouri |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Hemoglobin Volume: 5 ISSN: 0363-0269 ISO Abbreviation: Hemoglobin Publication Date: 1981 |
Date Detail:
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Created Date: 1982-03-26 Completed Date: 1982-03-26 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 7705865 Medline TA: Hemoglobin Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 579-89 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Hemoglobin A
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metabolism* Humans Kinetics Oxidation-Reduction Oxygen / blood Oxyhemoglobins / metabolism* Partial Pressure Phytic Acid / pharmacology* |
| Grant Support | |
ID/Acronym/Agency:
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5 R01 AM20181-02/AM/NIADDK NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Oxyhemoglobins; 7782-44-7/Oxygen; 83-86-3/Phytic Acid; 9034-51-9/Hemoglobin A |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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