The effect of sodium chloride and calcium chloride on the main phase transition of dimyristoylphosphatidylcholine

Differential scanning calorimetry is employed at a scan rate of 2 K h(-1) t o study the effects of sodium chloride and calcium chloride on the main pha se transition of dilute aqueous suspensions of dimyristoylphosphatidylcholi ne. The primary effect of sodium chloride over the concentration range stud ied, 0-5 molar, is to raise the transition temperature. In the case of calc ium chloride, studied over the range 0-2 molar, the increase in the transit ion temperature is much larger, and the transitions become unsymmetrical an d much broadened at concentrations above 0.75 M. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.