Table I.
Enrichment factors for several marker enzyme activities in the ER, GA, and PM fractions isolated from etiolated leek seedlings
Enzyme activities were measured and expressed as established in Sturbois-Balcerzak et al. (1999) and Vincent et al. (1999). The enrichment factors correspond to the ratios of the activities determined in the membrane fractions to that of the microsomal fraction from which the different membranes were purified. The percentage of inhibition of the K+-stimulated Mg2+ATPase activity in the PM by vanadate varied from 87% to 95%. Data are the mean values ± sd from three to five independent measurements.
| Marker Enzymes | Enrichment Factors
|
||
|---|---|---|---|
| ER | GA | PM | |
| NADPH cytochrome c reductase | 5.4 ± 1.4 | 0.46 ± 0.16 | 0.11 ± 0.04 |
| CDP-choline phosphotransferase | 4.2 ± 0.7 | 0.16 ± 0.07 | 0.07 ± 0.03 |
| Glucuronyl-transferase | 0.42 ± 0.13 | 3.8 ± 1.10 | 0.45 ± 0.13 |
| Glucane synthetase II | 0.03 ± 0.01 | 0.16 ± 0.07 | 5.5 ± 1.7 |
| K+-stimulated Mg2+ATPase | 0.02 ± 0.01 | 0.06 ± 0.05 | 16.8 ± 2.9 |