The flipase is inactivated in the PS-exposing subpopulation of sickle cells.

This plot is a typical example of the analysis of flipase activity and PS exposure in sickle cells following the labeling procedure described in Figure 8B (this experiment was typical of 4 similar experiments). After PE-SA/biotin-AV labeling, sickle cells were incubated with NBD-PS for 1 hour and back-extracted with BSA.