MONOLAYER BEHAVIOR OF MIXTURES OF BRANCHED-CHAIN PHOSPHOLIPIDS

Monolayers of two branched-chain phospholipids 2-methyl-hexadecanoyl)- sn-glycero-3-phosphocholine and dodecyl-hexadecanoyl)-sn-glycero-3-pho sphocholine) as well as a 1:1 mixture have been studied at the air/wat er interface by film balance measurements and x-ray diffraction, The m ethyl-branched phosphatidylcholine exhibits an oblique lattice structu re, whereas the quadruple-chain phosphatidylcholine shows a hexagonal packing of upright oriented aliphatic chains. The 1:1 mixture stabiliz es this hexagonal phase and proves the applicability of the molecule s hape concept to the packing in monolayers.