Fig. 7.

Intermembrane sphingolipid transfer evoked by 0.2 µM GM2AP (A, B) and by 2.0 µM Sap B (C). The sphingolipids listed in the figure are the respective fluorescent NBD derivatives with the NBD-amino group in the α position of their acyl chain (20). A: The transfer of 2-NBD-sulfatide from donor to acceptor membranes by GM2AP. In this experiment, donor liposomes contained either 2 mol% or 8 mol% TAMRA-MSPE as quencher. Donor liposomes in intermembrane transfer assays of 2-NBD-sphingolipids contained 2 mol% quencher (B, C). All assays were carried out in quadruplicate, and the results agreed within 5%.