Table I.
HPT specific activity in chloroplasts isolated from 2-, 4-, and 6-week-old wild-type and 35S::HPT1-11 and -54 leaves.
| Plant Age | Specific Activity
|
||
|---|---|---|---|
| Wild Type | 35S::HPT1-11 | 35S::HPT1-54 | |
| weeks | pmol h−1 mg−1 protein (-fold change) | ||
| 2 | 0.34 ± 0.06* | 1.69 ± 0.39 (5.1) | 1.36 ± 0.11 (4.1) |
| 4 | 0.11 ± 0.03* | 1.14 ± 0.48 (10.3) | 0.84 ± 0.27 (7.6) |
| 6 | 0.15 ± 0.10 | 0.71 ± 0.41 (4.7) | 0.75 ± 0.36 (5.0) |
HPT specific activity was determined using radiolabeled HGA and unlabeled PDP and expressed as an average ± sd of two to three independent experiments performed in triplicate. Values in parentheses represent -fold increases in the specific activity of transgenics compared with wild-type plants of the corresponding age. HPT specific activity in leaves of both 35S::HPT1 overexpressers was significantly higher than wild type (P < 0.05). Though there was a general trend of HPT specific activity decreasing in older relative to younger plants in each line, this was only statistically significant between 2- and 4-week-old wild-type plants (*, P < 0.01).