Puranam, Kasturi L and Raghothama, S and Balaram, P (1987) A proton-NMR study of bilirubin IX\alpha solubilization by cholate micelles: application of nuclear Overhauser effects. In: Biochimica et Biophysica Acta, Lipids and Lipid Metabolism, 922 (1). pp. 67-77.
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The solubilization of bilirubin IX\alpha (I) in aq. soln. by Na cholate micelles was examd. by 270-MHz 1H NMR spectroscopy. The incorporation of I into the micelles was accompanied by specific shifts of I vinyl and bridgehead protons and the C18 and C19 Me groups of the steroid. The obsd. chem. shifts showed a monotonic concn. dependence suggesting that changes in aggregation size are continuous. Nuclear Overhauser effects (NOE) were shown to be a useful probe or micellization. A 4:1 cholate (II)/I mixt. was investigated by difference NOE spectroscopy. The observation of intermol. NOE between peripheral protons of I and II were diagnostic of spatially proximate groups. Inter-II NOE increased in magnitude upon I incorporation, suggesting closer packing of steroid mols. on solubilization of the pigment. Intramol. NOE obsd. for solubilized I were consistent with a compact intramolecularly H-bonded conformation.
|Item Type:||Journal Article|
|Additional Information:||Copyright belongs to Elsevier Science Publishers B.V.|
|Keywords:||Bilirubin;Cholate micelle;NMR 1H-;Nuclear Overhauser effect;Bile salt|
|Department/Centre:||Division of Biological Sciences > Molecular Biophysics Unit
Division of Chemical Sciences > Sophisticated Instruments Facility
|Date Deposited:||06 Mar 2008|
|Last Modified:||19 Sep 2010 04:43|
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