Table I.
Enzyme activities assayed in extracts from antisense (JT 676, JT 594, JT 654, and JT 595) and sense (JT 1, JT 78, JT 98, and JT 62) AATP-tubers
| Enzymes | WT | JT 676 | JT 594 | JT 654 | JT 595 | JT 1 | JT 78 | JT 98 | JT 62 |
|---|---|---|---|---|---|---|---|---|---|
| Suc synthase | 1,901 ± 211 | 1,941 ± 110 | 2,261 ± 143 | 2,337 ± 111 | 2,079 ± 300 | 1,626 ± 130 | 2,538 ± 62 | 2,253 ± 89 | 2,541 ± 200 |
| UDPGlc pyrophosphorylase | 1,397 ± 70 | 1,640 ± 25 | 1,668 ± 18 | 1,435 ± 51 | 1,629 ± 17 | 1,318 ± 58 | 1,401 ± 31 | 1,473 ± 52 | 1,389 ± 63 |
| Alkaline invertase | 25.6 ± 1.1 | 35.7 ± 0.6 | 57.7 ± 4.3 | 60.9 ± 2.9 | 51.1 ± 4.1 | 24.5 ± 1.5 | 27.6 ± 1.9 | 28.0 ± 1.2 | 30.9 ± 3.5 |
| Acid invertase | 6.1 ± 0.4 | 17.6 ± 2.0 | 33.5 ± 4.5 | 41.9 ± 8.5 | 43.3 ± 12.2 | 10.6 ± 5.7 | 7.1 ± 1.4 | 7.1 ± 1.6 | 9.8 ± 1.6 |
| SPS (Vmax) | 506 ± 34 | 453 ± 84 | 492 ± 37 | 447 ± 41 | 575 ± 68 | 435 ± 67 | 493 ± 34 | 486 ± 34 | 379 ± 94 |
| SPS (Vsel) | 32.2 ± 8.3 | 49.8 ± 5.5 | 52.5 ± 6.4 | 57.4 ± 3.4 | 70.0 ± 10 | 25.9 ± 4.2 | 36.2 ± 14 | 24.4 ± 7.1 | 27.2 ± 1.0 |
| SPS (Vsel/Vmax) | 6.0 ± 1.3 | 14.6 ± 5.0 | 10.5 ± 0.6 | 13.1 ± 0.8 | 12.3 ± 1.1 | 6.6 ± 1.6 | 6.9 ± 2.3 | 5.3 ± 1.5 | 7.2 ± 0.3 |
| Glc6P-dehydrogenase (G6PDH) | 1,437 ± 105 | 1,383 ± 73 | 1,521 ± 8 | 1,467 ± 103 | 1,639 ± 41 | 1,398 ± 57 | 1,319 ± 54 | 1,408 ± 140 | 1,939 ± 216 |
| 6-Phosphogluconate-DH | 270 ± 16 | 381 ± 54 | 327 ± 12 | 347 ± 8 | 358 ± 3 | 273 ± 12 | 276 ± 12 | 315 ± 11 | 343 ± 30 |
| Phosphofruktokinase (PFK) | 101 ± 6 | 76 ± 4 | 110 ± 9 | 129 ± 16 | 104 ± 10 | 98 ± 7 | 119 ± 6 | 105 ± 10 | 109 ± 9 |
| Pyrophosphate: Fru-6-phosphate: phosphotransferase (PFP) | 1,125 ± 69 | 926 ± 9 | 1,152 ± 48 | 940 ± 101 | 1,084 ± 60 | 1,089 ± 69 | 1,112 ± 41 | 1,160 ± 123 | 1,265 ± 90 |
| Glycerinaldehydephosphate dehydrogenase (GAP-DH) | 2,087 ± 255 | 1,616 ± 115 | 2,153 ± 245 | 2,094 ± 271 | 2,209 ± 97 | 1,959 ± 232 | 2,049 ± 304 | 1,698 ± 256 | 2,350 ± 346 |
| Pyruvatekinase | 379 ± 48 | 340 ± 38 | 418 ± 17 | 313 ± 36 | 281 ± 35 | 423 ± 65 | 528 ± 46 | 333 ± 93 | 376 ± 58 |
| PEP carboxylase | 97 ± 10 | 172 ± 18 | 186 ± 14 | 191 ± 16 | 232 ± 18 | 99 ± 7 | 129 ± 19 | 141 ± 11 | 131 ± 5 |
| PEP phosphatase | 517 ± 66 | 388 ± 47 | 608 ± 33 | 858 ± 120 | 608 ± 21 | 474 ± 44 | 698 ± 12 | 470 ± 101 | 479 ± 69 |
| ADPGlc pyrophosphorylase | 893 ± 75 | 723 ± 37 | 686 ± 35 | 812 ± 38 | 680 ± 51 | 857 ± 152 | 1,088 ± 29 | 1,024 ± 94 | 998 ± 66 |
Results (nmol g fresh wt−1 min−1) are the mean ± se (n = 5 separate tubers from different plants). Suc phosphate synthase (SPS) was measured under two different assay conditions: Vmax assay (12 mm Fru6P, 36 mm Glc6P, and 6 mm UDPGLc), or Vsel assay (2 mm Fru6P, 6 mm Glc6P, 6 mm UDPGlc, and 5 mm Pi).