Table II.
Effects of leaf aging on the activity of the enzymes of nitrogen metabolism in transgenic tobacco plants, which harbor the GLU1 promoter of the Arabidopsis Fd-Glu synthase fused to a GUS reporter gene (GLU1::GUS)
Enzyme assays were carried out in two transgenic lines: GLU1∷GUS*1 and GLU1∷GUS*2.
| Nitrogen Metabolism Enzymes
|
Young Leaves
|
Old Leaves
|
||
|---|---|---|---|---|
| GLU1∷GUS*1 | GLU1∷GUS*2 | GLU1∷GUS*1 | GLU1∷GUS*2 | |
| Enzyme activity: nmol mg−1 protein min−1 | ||||
| NR | 15.50 ± 1.40 | 18.76 ± 2.06 | 4.70 ± 0.40 | 4.67 ± 0.42 |
| GS | 90.50 ± 8.21 | 102.27 ± 11.25 | 22.67 ± 2.01 | 34.00 ± 3.10 |
| Fd-GOGAT | 16.17 ± 1.48 | 21.51 ± 2.11 | 4.50 ± 0.38 | 5.81 ± 0.55 |
| NADH-GOGAT | 0.33 ± 0.03 | 0.41 ± 0.04 | 0.11 ± 0.01 | 0.14 ± 0.02 |
| NADH-GDH | ||||
| Aminating | 33.77 ± 3.14 | 31.07 ± 3.01 | 78.50 ± 7.21 | 76.12 ± 8.37 |
| Deaminating | 14.17 ± 1.28 | 13.89 ± 1.81 | 21.33 ± 1.98 | 19.51 ± 2.15 |