Selected examples of transitions in lipid mixtures

Saturated glycero- and sphingophospholipids other than phosphatidylcholines and phos-phatidylglycerols, that cannot form tilted Lp- phases, form instead the gel Lp phase. In these cases, the gel-to-fluid Lp-to-La thermotropic transition (without a rippled intermediate) has very similar properties to that of the main transition in, e.g. DPPC (see Table 4.1). 

The transition temperatures (Tm) of both the Pp-Lm and Lp-L transitions are very sensitive to the nature of the fatty acyl hydrocarbon chains, the temperatures decreasing with chain length, and, very markedly, with the presence of cw-double bonds in the fatty acyl residues. This is shown, for example, by the decrease in in the progression distearoyl (C18 0), dioleoyl (C18 l), dilinoleoyl (C18 2) phosphatidylcholines (Table 4.1). 

Some phospholipids, typically phosphatidylethanolamines (PE), can undergo under certain conditions a thermotropic L —Hn transition that can be conveniently monitored by DSC. 

Phase diagrams of two- and multicomponent lipid mixtures are complicated by at least three different factors  

CH4 DIFFERENTIAL SCANNING CALORIMETRY IN THE STUDY OF LIPID STRUCTURES 

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