Characterization of the interactions of NADH with the dimeric and tetrameric states of methaemoglobin

Jacobsen M.P. and Winzor D.J. (1995) Characterization of the interactions of NADH with the dimeric and tetrameric states of methaemoglobin. Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular, 1246 1: 17-23. doi:10.1016/0167-4838(94)00174-F


Author Jacobsen M.P.
Winzor D.J.
Title Characterization of the interactions of NADH with the dimeric and tetrameric states of methaemoglobin
Journal name Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
ISSN 0167-4838
Publication date 1995-01-05
Sub-type Article (original research)
DOI 10.1016/0167-4838(94)00174-F
Volume 1246
Issue 1
Start page 17
End page 23
Total pages 7
Subject 1303 Specialist Studies in Education
1304 Biophysics
1312 Molecular Biology
1315 Structural Biology
Abstract The binding of NADH to the dimeric (αβ) and tetrameric (α2β2) states of human aquomethaemoglobin has been characterized by sedimentation equilibrium studies of the effect of the concentration of free ligand on the macromolecular state of the haemoprotein. Both macromolecular states of aquomethaemoglobin exhibit a single binding site for NADH, which interacts approximately tenfold more strongly (6000 cf. 700 M-1) with the tetramer under the conditions studied (pH 6.0, I 0.10). Because the structure of aquomethaemoglobin resembles that of the deoxy state of haemoglobin, there is a high probability that organic phosphates also bind to dimeric deoxyhaemoglobin, a phenomenon which is not considered in thermodynamic treatments of the interplay between oxygen binding and its allosteric inhibition by 2,3-bisphosphoglycerate. Fortunately, the equilibrium constant for deoxyhaemoglobin self-association is so large that neglect of the interaction between allosteric inhibitor and dimeric haemoglobin is an oversight that should have no deleterious implications in the resultant thermodynamic analysis of the interplay between the preferential interactions of oxygen and organic phosphate with the various macromolecular states of deoxyhaemoglobin.
Keyword Methemoglobin
Organic
phosphate
Preferential binding
Self-association
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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