Publication Date:
1992-05-01
Description:
The oxygen affinity of hemoglobin varies linearly with the chemical potential of water in the bathing medium, as seen from the osmotic effect of several neutral solutes, namely sucrose, stachyose, and two polyethyleneglycols (molecular weights of 150 and 400). The data, analyzed either by Wyman linkage equations or by Gibbs-Duhem relations, show that approximately 60 extra water molecules bind to hemoglobin during the transition from the fully deoxygenated tense (T) state to the fully oxygenated relaxed (R) state. This number, independent of the nature of the solute, agrees with the difference in water-accessible surface areas previously computed for the two conformations. The work of solvation in allosteric regulation can no longer go unrecognized.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Colombo, M F -- Rau, D C -- Parsegian, V A -- New York, N.Y. -- Science. 1992 May 1;256(5057):655-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Biochemistry and Metabolism, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1585178" target="_blank"〉PubMed〈/a〉
Keywords:
Allosteric Regulation/physiology
;
Chemistry, Physical
;
Hemoglobins/*chemistry/metabolism
;
Oligosaccharides/pharmacology
;
Osmotic Pressure
;
Oxygen/metabolism
;
Physicochemical Phenomena
;
Polyethylene Glycols/pharmacology
;
Protein Conformation
;
Sucrose/pharmacology
;
Thermodynamics
;
Water/metabolism/*pharmacology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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