Table II.
Effect of GSH precursors on demand-driven de novo GSH biosynthesis during incubation of Arabidopsis cells with MCB
| Treatment | Resting Level of GSH | Estimated Lag Time | Rate of GSH Biosynthesis |
|---|---|---|---|
| % | min | nmol g fresh wt−1 min−1 | |
| Murashige and Skoog medium supplemented with 3% (w/v) Suc (control) | 100 | 120–180 | 8.9 ± 1.4 (6) |
| +1 mm Glu | 102 ± 6 | 120–180 | 8.9 ± 1.5 (5) |
| +1 mm Gly | 97 ± 8 | 120–180 | 8.8 ± 1.4 (5) |
| +1 mm Cys | 105 ± 15 | 120–180 | 10.6 ± 1.8 (5) |
| +0.1 mm Cys | 95 ± 12 | 120–180 | 9.3 ± 1.7 (5) |
| +1 mm Glua | 101 ± 5 | 120–180 | 8.8 ± 1.9 (5) |
| +1 mm Glya | 102 ± 9 | 120–180 | 8.7 ± 1.6 (5) |
| +1 mm Cysa | 169 ± 17 | 120–180 | 10.3 ± 2.0 (5) |
| −SO42− | 102 ± 5 | nd | 0.0 ± 0.0 (6) |
| +1 mm SO42− | 101 ± 7 | 120–180 | 8.9 ± 1.4 (7) |
| +10 mm SO42− | 99 ± 11 | 120–180 | 9.0 ± 1.2 (7) |
Cells were always labeled with 50 to 100 μm MCB over 6 h. Precursors were removed from or added to the labeling solution at the start of labeling. All values are given as mean ± sd with the no. of experiments in parentheses. The control medium contained 1.73 mm SO42−. nd, Not detected.
a
Cells were pre-incubated for 10 to 12 h.