TABLE 1.
Quantity of cell-associated PTS1 and efficiency of toxin delivery to the cytosol
| Condition | PTS1 (ng) (mean ± SD) | No. of PTS1 molecules/cell | % surface-associated PTS1 |
|---|---|---|---|
| Pulse | |||
| Membrane | 119 ± 29a | 1,200,000 | 100 |
| Chase | |||
| Cytosol | 3.7 ± 0.4 | 38,000 | 3.1 |
| Medium | 0.3 ± 0.1 | 3,000 | 0.25 |
a
PT standards (see Fig. S3C and D in the supplemental material) were used to calculate the amount of PT on the plasma membrane of pulse-loaded cells (Fig. 3C). This value was then corrected for the molar ratio of PTS1 in the PT holotoxin.