Table 1.

Total and Membrane LPC Concentrations Giving 50% Fusion Inhibition

LPC	Total LPC concentration giving 50% fusion inhibition	Membrane concentration of LPC giving 50% fusion inhibition
	μM	%
Lauroyl	240 ± 50	4.1 ± 0.5
Myristoyl	23 ± 2	5.8 ± 0.5
Palmitoyl	6.5 ± 1	8.7 ± 2
Stearoyl	4.1 ± 2	9.9 ± 2

The total LPC concentration in the medium giving 50% of fusion inhibition was calculated from the graph in Fig. 2. The amount of LPC incorporated in the membrane, and thus the membrane concentration of LPC giving 50% of inhibition, were calculated as indicated in Materials and Methods.