title: Effect of submicellar concentrations of conjugated and unconjugated bile salts on the lipid bilayer membrane.
abstract: The interaction of submicellar concentrations of various physiologically important unconjugated [sodium deoxycholate (NaDC), sodium cholate (NaC)] and conjugated [sodium glycodeoxycholate (NaGDC), sodium glycocholate (NaGC), sodium taurodeoxycholate (NaTDC), sodium taurocholate (NaTC)] bile salts with dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) small unilamellar vesicles in solid gel (SG) and liquid crystalline (LC) phases was investigated using the excited-state prototropism of 1-naphthol. Steady-state and time-resolved fluorescence of the two excited-state prototropic forms of 1-naphthol indicate that submicellar bile salt concentration induces hydration of the lipid bilayer membrane into the core region. This hydration effect is a general phenomenon of the bile salts studied. The bilayer hydration efficiency of the bile salt follows the order NaDC > NaC > NaGDC > NaTDC > NaGC > NaTC for both DPPC and DMPC vesicles in their SG and LC phases.
authors.affiliation: Department of Chemistry,  Indian Institute of Technology  Madras, Chennai 600 036, India.
authors.forename: Monalisa
authors.initials: M
authors.lastname: Mohapatra
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Mishra
mesh_terms: D001647:Bile Acids and Salts / Q000737:chemistry*; D003460:Crystallization; D005453:Fluorescence; D008051:Lipid Bilayers; D008823:Micelles
chemical_list: D001647:Bile Acids and Salts; D008051:Lipid Bilayers; D008823:Micelles