TABLE 1.
Half-times of transbilayer movement of NBD-labeled PC and PE in yeast microsomes and rat liver ER vesicles at 22°Ca
| Organism and NBD-PL | Half-time for:
|
|
|---|---|---|
| Outward movement (s) | Inward movement (s) | |
| Yeast C6-NBD-PC | 103 ± 20 | 176 ± 39 |
| Rat liverb | ||
| C6-NBD-PC | 98 ± 9 | 148 ± 12 |
| C6-NBD-PE | 81 ± 8 | 62 ± 4 |
a
Experimental traces (see Fig. 2) were fitted according to the model to obtain the rate constants of the outward and inward movements of phospholipid analogues, k+1 and k−1, respectively (see Materials and Methods). Half-times of the outward and inward movements across the ER membrane were derived from k+1 and k−1, respectively, according to the formula τ = (ln2)/k, where τ is the half-time. Data shown are means ± standard deviations for two independent experiments. For each experiment, three single kinetics were averaged and subsequently analyzed.
b
Data are from Marx et al. (23).