Fluorescent probe and NMR studies of the aggregation of bile salts in aqueous solution

Paul, Ranajit and Mathew, MK and Narayanan, R and Balaram, P (1979) Fluorescent probe and NMR studies of the aggregation of bile salts in aqueous solution. In: Chemistry and Physics of Lipids, 25 (4). pp. 345-356.

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Abstract

The binding of the fluorescent probes 1-anilino-8-naphthalene sulfonate and dansyl cadaverine to the sodium salts of cholic, deoxycholic and dehydrocholic acids has been investigated. Enhanced probe solubilisation accompanies aggregation. Monitoring of fluorescence intensities as a function of bile salt concentration permits the detection of primary micelle formation, as well as secondary association. The transition concentrations obtained by fluorescence are in good agreement with values determined for the critical micelle concentrations, by other methods. Differences in the behaviour of cholate and deoxycholate have been noted. Fluorescence polarisation studies of 1,6-diphenyl-1,3,5-hexatriene solubilised in bile salt micelles suggest a higher microviscosity for the interior of the deoxycholate micelle as compared to cholate. 1H NMR studies of deoxycholate over the range 1–100 mg/ml suggest that micelle formation leads to a greater immobilisation of the C18 and C19 methyl groups as compared to the C21 methyl group. Well resolved 13C resonances are observed for all three steroids even at high concentration. Both fluorescence and NMR studies confirm that dehydrocholate does not aggregate.

Item Type:	Journal Article
Publication:	Chemistry and Physics of Lipids
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Biological Sciences > Biochemistry
Date Deposited:	03 Feb 2010 09:41
Last Modified:	19 Sep 2010 05:44
URI:	http://eprints.iisc.ac.in/id/eprint/23062

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