B. D. Fleming, C. Raynor, K. Keough
Jul 13, 1983
Citations
0
Influential Citations
16
Citations
Journal
Biochimica et Biophysica Acta
Abstract
Abstract Some properties of monolayers of 1- palmitoyl -2- oleoyl -sn- glycero -3- phospho -rac- glycerol (POPG) alone or of POPG in mixtures with 1,2- dipalmitoyl -sn- glycero -3- phosphocholine (DPPC) have been measured near 35°C during dynamic compression and expansion at 3.6 cm2·s−1. (2) The mean values of minimum surface tension (corresponding to maximum surface pressure) which could be obtained with pure POPG monolayers at high compression ranged from 15 to 18 mN·m−1 in the presence of Na+, Ca2+ or low pH (2.0) in the subphase. (3) The presence of Ca2+ or low pH in the subphase increased the collapse plateau ratios obtained on cyclic compression. This might represent enhanced respreading into the monolayer of pure POPG from a collapsed form during reexpansion of the surface. (4) Monolayers containing 10% or 30% POPG and 90% or 70% DPPC could be compressed to surface tensions approaching zero. (5) In such mixed monolayers, 10% or 30% POPG did not appear to enhance respreading, as measured by collapse plateau ratios, in the presence of Na+ or Ca2+ in the subphase.