Partition of parinaroyl phospholipid probes between solid and fluid phosphatidylcholine phases

Publisher Website
Google Scholar
Abstract
The partitioning of parinaroyl phospholipid probes between solid- and fluid-phase phospholipid is examined. The immiscible model system dipalmitoyl-PC [PC = phosphatidylcholine] and palmitoyldocosahexaenoyl-PC is used. Fluorescence quantum yields and fluorescence polarization are used to calculate Kps/f, the solid to fluid phase partition coefficient of each probe. Like free trans-parinaric acid (9,11,13,15-all-trans-octadecatetraenoic acid), 1-palmitoyl-2-trans-parinaroyl-PC and 1-palmitoyl-2-trans-parinaroyl-PE [PE = phosphatidylethanolamine] partition strongly into solid phase with mean Kps/f of 7 .+-. 4 and 9 .+-. 5, respectively. Like free cis-parinaric acid (9,11,13,15-cis,trans,trans,cis-octadecatetraenoic acid), another group of phospholipid probes prefer fluid phase just slightly or partition equally between fluid and solid phases. The Kps/f of 1-palmitoyl-2-cis-parinaroyl-PC is 0.6 .+-. 0.2, that of 1-palmitoyl-2-cis-parinaroyl-PE is 1.0 .+-. 0.3, that of 1-oleoyl-2-trans-parinaroyl-PC is 0.6 .+-. 0.3, and that of 1-oleoyl-2-trans-parinaroyl-PE is 0.7 .+-. 0.3. Two probes partition more strongly into fluid-phase phospholipid. These are 1-oleoyl-2-cis-parinaroyl-PC with a Kps/f of 0.2 .+-. 0.1 and 1-oleoyl-2-cis-parinaroyl-PE with a Kps/f of 0.4 .+-. 0.4.