Activity and nucleotide content in amk mutants
Rosette leaves of seedlings were analyzed after 21 d of growth on plates containing one-half-strength MS with 0.5% Suc. Activity data are given as percentage of the controls, with forward reaction at 4.2 ± 1.3 nmol s−1 (mg protein)−1 and backward reaction at 4.0 ± 1.5 nmol s−1 (mg protein)−1. Each data point represents the mean and sd of seven replicates for amk2, nine replicates for congenic wild-type and heterozygous plants, and four replicates for amk5. Significant differences (P < 0.1) using unpaired two-tailed t tests are marked with an asterisk.
| amk2 | AMK | amk5 | |
|---|---|---|---|
| Activity | |||
| Forward reaction (% of control) | 79 ± 15.7* | 100 ± 19.2 | 99 ± 7.3 |
| Backward reaction (% of control) | 63 ± 14.9* | 100 ± 4.3 | 101 ± 15.5 |
| Metabolite content | |||
| AMP (nmol g FW−1) | 3.9 ± 1.8 | 5.4 ± 2.4 | 7.5 ± 1.0 |
| ADP (nmol g FW−1) | 8.5 ± 4.5* | 25.5 ± 8.8 | 31.6 ± 2.0 |
| ATP (nmol g FW−1) | 18.7 ± 7.4* | 50.4 ± 19.4 | 58.0 ± 10.1 |
| Purine (nmol g FW−1) | 32.8 ± 8.4* | 89.5 ± 26.2 | 110 ± 15.9 |
| Adenylate energy charge ([ATP] + [0.5 × ADP]) × ([ATP] + [ADP] + [AMP])−1 | 0.72 ± 0.09* | 0.79 ± 0.05 | 0.77 ± 0.03 |