Abstract：
:The gel to liquid-crystalline phase transition temperatures of dispersions of mixed-acid sn-1,2-lecithins which contain one unsaturated and one saturated fatty acid have been studied by differential scanning calorimetry. The temperature for 1-oleoyl-2-palmitoyl-sn-glycero-3-phosphocholine (containing no reversed isomer) was -9.3 degrees C while that for 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (containing 8% of the reversed isomer) was -2.6 degrees C. The temperature for 2-oleoyl-1-stearoyl-sn-glycero-3-phosphocholine (containing 6% of the reversed isomer) was 6.3 degrees C while that for 1-oleoyl-2-stearoyl-sn-glycero-3-phosphocholine (containing 18% of the reversed isomer) was 8.6 degrees C. The differences in transition temperatures for the isomers of a pair containing the same two acids were consistent with those observed for positional isomers of saturated mixed-acid lecithins in that the isomer of the pair which had the longer fatty acid in the sn-1 position had the lower temperature. The phase transition temperatures of pairs of isomers containing palmitate and oleate at the sn-1 and -2 positions were different by at least 6.7 degrees C, while those containing stearate and oleate were different by at least 2.3 degrees C. Differences in the chain lengths of the fatty acids at the two positions of the glycerol appear to predominate over differences in the depths of the double bonds in the bilayer in determining the transition temperatures.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Davis PJ,Fleming BD,Coolbear KP,Keough KMdoi
10.1021/bi00515a051subject
Has Abstractpub_date
1981-06-09 00:00:00pages
3633-6issue
12eissn
0006-2960issn
1520-4995journal_volume
20pub_type
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