Zw. Yu et al., PHASE-BEHAVIOR OF DISTEAROYLPHOSPHATIDYLETHANOLAMINE IN GLYCEROL - A THERMAL AND X-RAY-DIFFRACTION STUDY, Biochimica et biophysica acta. Biomembranes, 1237(2), 1995, pp. 135-142
The phase behaviour of 1,2-distearoylphosphatidylethanolamine in glyce
rol has been examined using differential scanning calorimetry and real
-time synchrotron X-ray diffraction methods. Dry phospholipid and phos
pholipid dispersed in glycerol over the concentration range 2.4%-90% (
w/w) was equilibrated for 30 min at 20 degrees C and thermal and struc
tural parameters on the temperature range 60 degrees C to 110 degrees
C recorded during an initial heating and subsequent reheating. The cha
racteristic feature of the initial heating scan was a direct lamellar
crystalline to inverted hexagonal phase transition. In the subsequent
cooling scan a lamellar gel structure was formed from the non-lamellar
phase which transformed, on reheating, to a lamellar crystalline phas
e in which the acyl chain packing was tilted with respect to the bilay
er plane, The mechanism of the formation of the two crystalline phases
was examined in the context of a relaxation model, where the liquid-c
rystal phase below the transition temperature from lamellar crystallin
e phase is metastable. A binary phase diagram over the temperature ran
ge 60 degrees C to 110 degrees C has been constructed.