ISSN:
0377-0486
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Measurements of the depolarization ratio of the four resonant Raman lines at 1375 cm-1, 1506 cm-1, 1583 cm-1, and 1638 cm-1 were performed for all exciting wavelengths of an Argon ion laser. The results show a significant variation of the depolarization ratio in the wavelength region between the Soret- and β-bands. The dispersion curves have a different shape for the four Raman lines. Measurements of the depolarization ratio at three pH-values (pH = 6.3, pH = 7.4, pH = 8.0) and two haemoglobin concentrations (c = 1.2 × 10-4 M, c = 5 × 10-5M) of the solution show that the concentration and the pH-value change the dispersion curve in a similar way. The depolarization ratio of the 1375-Raman line at 496.5 nm excitation wavelength was measured for different concentrations in a region between 4 × 10-4M and 4 × 10-5M. With decreasing concentration the DPR increases. This effect is interpreted as being caused by the dimerization of the tetrameric oxyhaemoglobin molecule. The dispersion curves ρ(λ) are interpreted in terms of mode mixing of the molecular vibrations of the haem due to symmetry lowering of its environment. This symmetry change is induced by interactions of the solvent with the charged and polar groups on the surface of the globular protein.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jrs.1250130208
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