Comparative kinetics of CL and CLOOH transfer between liposomes; spontaneous versus nsLTP-facilitated transfer. A, spontaneous transfer of CL (○) and CLOOH (△) from SUVs to LUVs is shown. Reaction mixtures at 37 °C contained POPC/CL/LacPE (7:2:1 by mol) or POPC/CL/CLOOH/LacPE (7:1:1:1 by mol) SUV donors and POPC LUV acceptors (1:5 lipid mol ratio). At the indicated incubation times, the membranes were separated by agglutination, and CL/CLOOH in the LUV fraction was analyzed by HPLC using A205 and A232 for CL and CLOOH detection, respectively. B, nsLTP-enhanced CL (○) and CLOOH (△) transfer. Reaction mixtures were the same as in A except for the inclusion of nsLTP (50 μg/ml). Timed samples were quenched on ice and analyzed for LUV-acquired CL or CLOOH as described in A. Incubations in the absence and presence of nsLTP were carried out simultaneously. Plotted values in A and B are the means ± S.E. of values from three separate experiments. Cd(to) and Ca(t) denote analyte concentration in donor SUVs at time 0 and in acceptor LUVs at time t, respectively. Calculated apparent first-order rate constants for transfer are as follows: A, 2.2 ± 0.3 × 10−3 h−1 (CL), 7.3 ± 1.5 × 10−3 h−1 (CLOOH); B, 1.3 ± 0.2 × 10−2 h−1 (CL), 9.8 ± 0.2 × 10−2 h−1 (CLOOH).