Table V.
Effects of MCO on the three peptidic activities of 20S proteasomes isolated from starved and non-starved maize root tips
| 20S Proteasome | Chymotrypsin Like | Trypsin Like | PGPH |
|---|---|---|---|
| nmol mg−1 h−1 | |||
| T0 | |||
| Nonoxidized | 104 ± 3 | 204 ± 8 | 54 ± 5 |
| Oxidized | 220 ± 7 | 140 ± 12 | 67 ± 1 |
| T24 starved | |||
| Nonoxidized | 192 ± 0 | 159 ± 15 | 58 ± 9 |
| Oxidized | 162 ± 1 | 124 ± 8 | 45 ± 1 |
| T24 + Glc | |||
| Nonoxidized | 124 ± 3 | 185 ± 7 | 42 ± 6 |
| Oxidized | 237 ± 4 | 154 ± 8 | 77 ± 12 |
Isolated 20S proteasomes from T0, T24-starved, and T24 + Glc root tips were oxidized for 3 h at 37°C in the presence of Fe2+/ascorbate. Control proteasomes (nonoxidized) were incubated in parallel without Fe2+/ascorbate. Peptidic activities of oxidized and nonoxidized proteasomes were then measured as described in “Materials and Methods.” Values are the mean of six measurements from three independent experiments.