Table I.
Specific activities of membrane-bound proteins in microsomes and plasma membrane vesicles isolated from soybean roots
Membranes were isolated from the root apices of 8-d-old Suzunari seedlings. Assays were conducted at 30°C The inhibitor-sensitive activity was calculated by subtracting the ATP-hydrolytic activity in the presence of inhibitor from the activity of the control. The values are means of three replicates of two independent experiments.
| Type | Microsome Fraction | Plasma Membrane Fraction |
|---|---|---|
| μmol min−1 mg−1 protein | ||
| VA-sensitive ATPase (1 mm) | 0.11 ca (7.15) | 1.16 a (91.3) |
| Nitrate-sensitive ATPase (50 mm) | 0.26 b (17.1) | 0.02 b (1.58) |
| Azide-sensitive ATPase (1 mm) | 0.13 c (8.55) | 0.03 b (2.37) |
| Molybdate-sensitive ATPase (1 mm) | 0.74 a (48.7) | 0.05 b (3.95) |
| NADH cyt-c reductase | 0.31 b (20.5) | 0.01 b (0.80) |
a
Different letters in the same column indicate a significant difference at the 0.05 level, according to Duncan's Multiple Range Test. Data in parentheses show the percentage of each enzyme to the total.