Synthesis and properties of dimeric glycerophospholipid: 2,2'-dotriacontanedioylbis(1-palmitoyl-sn-glycero-3-phosphocholine).

2,2'-Dotriacontanedioylbis(1-palmitoyl-sn-glycero-3-phosphocholine ) was synthesized chemically as a dimeric version of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine. Upon sonication in water, the bipolar lipid furnished a planar membrane of about 50 Angstrom thickness with gel-to-liquid crystalline phase transition constants of Tm = 53.4 degrees C, DeltaH = 20.9 kcal/mol, and DeltaS = 64.0 e.u. In an air/water interface, the lipid displayed unique surface pressure-surface area isotherms with a limiting area of 105-190 Angstrom/molecule at 10-20 degrees C. The lipid was a substrate of phospholipase A2 (Naja mocambique), which afforded 1-palmitoyl-sn-glycero-3-phosphocholine and dotriacontanedioic acid as final products.