Table I.
Effect of reduced NADME activity on other enzyme activities in potato tubers
| Enzyme | Wild Type | 35S-ME11 | 35S-ME10 | PAT-ME9 | PAT-ME10 |
|---|---|---|---|---|---|
| nmol min−1 g−1 fresh wt | |||||
| Citrate synthase | 75 ± 5 | 69 ± 3 | 73 ± 2 | 80 ± 3 | 72 ± 4 |
| Isocitrate dehydrogenase | 26 ± 4 | 19 ± 2 | 22 ± 2 | 24 ± 5 | 31 ± 3 |
| Malate dehydrogenasea | 28 ± 3 | 28 ± 2 | 29 ± 3 | 30 ± 2 | 26 ± 1 |
| Phosphofructokinase (ATP) | 47 ± 1 | 52 ± 4 | 46 ± 1 | 35 ± 1b | 82 ± 21 |
| Phosphofructokinase (pyrophosphate) | 136 ± 32 | 143 ± 28 | 135 ± 21 | 160 ± 76 | 138 ± 9 |
| Phosphoglyceromutase | 2,058 ± 327 | 1,106 ± 393 | 1,414 ± 357 | 699 ± 52b | 792 ± 62b |
| Phosphoglycerate kinase | 456 ± 172 | 579 ± 91 | 603 ± 114 | 723 ± 205 | 823 ± 50 |
| Enolase | 111 ± 15 | 109 ± 35 | 126 ± 27 | 134 ± 27 | 106 ± 32 |
| PEP carboxylase | 75 ± 12 | 55 ± 15 | 78 ± 14 | 107 ± 47 | 46 ± 5 |
| Pyruvate kinase | 755 ± 40 | 719 ± 30 | 665 ± 56 | 712 ± 32 | 1,061 ± 76 |
| ADP-Glc pyrophosphorylase | 104 ± 19 | 98 ± 22 | 87 ± 17 | 92 ± 20 | nd |
| Total starch synthase | 126 ± 6 | 124 ± 3 | 116 ± 5 | 117 ± 15 | nd |
| Alkaline pyrophosphatase | 604 ± 156 | 442 ± 237 | 663 ± 210 | 587 ± 79 | nd |
| Starch phosphorylase | 212 ± 27 | 271 ± 24 | 234 ± 44 | 246 ± 28 | nd |
| Total amylolytic activity | 184 ± 41 | 102 ± 21 | 124 ± 50 | 127 ± 58 | nd |
The activity of the indicated enzymes was measured in tuber extracts from wild type and far transgenic lines. All values are from a single harvest, which is representative of at least one other harvest for each enzyme. Values are mean ± se (n = 3–5 tubers). nd, Not determined.
a
Malate dehydrogenase activities are expressed in units of μmol min−1 g−1 fresh wt.
b
Significantly different from wild type (P < 0.05; Student's t test).