The binding of Ca2+ to taurine and glycine-conjugated bile salt micelles.

The binding of Ca2+ to micelles of glycine and taurine bile acid conjugates was studied using a Ca2+-specific electrode. An investigation of the effect of buffer concentration, pH, added electrolyte and lecithin was also carried out. The observed results indicate that the binding of Ca2+ to bile salt micelles is dependent on both the number of hydroxyl groups on the steroid nucleus as well as on the nature of the head conjugating group, viz. glycine or taurine. It is speculated that the binding of Ca2+ to bile salt micelles may act as one of the mechanisms to lower Ca2+ activity in bile and thus reduce its tendency to precipitate as insoluble calcium salts and further growth into gallstones.