Light-scattering studies on bile acid salts II: pattern of self-association of sodium deoxycholate, sodium...

The pattern of self-association of the bile salts sodium deoxycholate, sodium glycodeoxycholate, and sodium taurodeoxycholate was investigated in aqueous electrolyte solutions by the light-scattering technique. The turbidity of the bile salt solutions was obtained over the concentration range of 0-20 mg/ml at 25 degrees. These data were analyzed according to a monomer-micellar equilibrium model and a stepwise association model. Comparison of the light-scattering data with these models suggests that the monomer-micellar model may be inappropriate. Analysis of the data according to the stepwise association model suggests that the dihydroxy bile salts associate to form dimers, trimers, and tetramers in addition to a larger aggregate which varies in size depending on the degree of conjugation of the bile salt.