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Temperature dependence of macromolecular interactions in dilute and concentrated hemoglobin solutions
Author(s) -
Veldkamp Wilfrid B.,
Votano Joseph R.
Publication year - 1980
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1980.360190108
Subject(s) - chemistry , hemoglobin , diffusion , macromolecule , solvent , intramolecular force , thermodynamics , viscosity , organic chemistry , biochemistry , physics
We studied the temperature‐dependent effects of intramolecular interactions on the mutual diffusion coefficient of normal human oxygenated hemoglobin in salt solution. We used photon correlation spectroscopy to observe this temperature dependence of the mutual diffusion coefficient of two protein concentrations (1.25 and 17.0 g %) between 13 and 37°C. This coefficient was our probe for monitoring temperature‐dependent structural changes of hydrated hemoglobin in solution. Comparison of our measured diffusion coefficient with that predicted by the Stokes‐Einstein relationship in terms of solvent or solution viscosity showed a clear transition in the conformation of hemoglobin at approximately 22°C, independent of the hemoglobin concentration. We postulated that at this physiological temperature, a considerable quaternary rearrangement of the hemoglobin chains takes place. We believe this rearrangement changes the effective volume and the hydration sphere of the hemoglobin macromolecule.