Table 4 Primary, Intermediate, and Secondary Metabolic Pathways in Citrus
Pathway | Enzymatic Activity | EC reaction | Unigenesa | ESTsb |
|---|---|---|---|---|
Glycolysis | Hexokinase | 2.7.1.1 | 4 (2)c | 6 (4)d |
| Â | Glucose-6-phosphoisomerase | 5.3.1.9 | 6 (1) | 16 (1) |
| Â | 6-Phosphofructokinase | 2.7.1.11 | 10 | 35 |
| Â | Fructose 1,6-biphosphate aldolase | 4.1.2.13 | 12 (7) | 71 (9) |
| Â | Triose phosphate isomerase | 5.3.1.1 | 8 (1) | 22 (1) |
| Â | Glyceraldehyde 3-P dehydrogenase | 1.2.1.12 | 8 (2) | 52 (8) |
| Â | Phosphoglycerate kinase | 2.7.2.3 | 6 (1) | 15 (3) |
| Â | Phosphoglycerate mutase | 5.4.2.1 | 1 | 5 |
| Â | Enolase | 4.2.1.11 | 7 (4) | 28 (5) |
| Â | Pyruvate kinase | 2.7.1.40 | 10 (1) | 69 (9) |
Tricarboxylic acid cycle (Krebs cycle) | Citrate synthase | 4.1.3.7 | 2 | 13 |
| Â | Aconitase | 4.2.1.3 | 6 (1) | 31 (1) |
| Â | Isocitrate dehydrogenase | 1.1.1.42 | 3 | 59 |
| Â | a-Ketoglutarate dehydrogenase complex | 1.2.4.2 | No hits | No hits |
| Â | Succinyl-CoA synthetase | 6.2.1.5 | 2 | 14 |
| Â | Succinate dehydrogenase | 1.3.5.1 | 2 | 20 |
| Â | Fumarase | 4.2.1.2 | 3 (2) | 30 (5) |
| Â | Malate dehydrogenase | 1.1.99.16 | 4 | 24 |
Oxidative/nonoxidative pentose phosphate pathway | Glucose 6-P-1-dehydrogenase | 1.1.1.49 | 4 | 4 |
| Â | 6-Phosphogluconolactonase | 3.1.1.31 | 2 | 10 |
| Â | 6-Phosphogluconate dehydrogenase | 1.1.1.44 | 15 | 47 |
| Â | Ribose-5-P isomerase | 5.3.1.6 | 3 | 12 |
| Â | Ribose-5-P 3-epimerase | 5.1.3.1 | No hits | No hits |
| Â | Transketolase | 2.2.1.1 | 3 (2) | 22 (11) |
| Â | Transaldolase | 2.2.1.2 | 4 (2) | 20 (17) |
Aromatic amino acid biosynthesis | 3-Deoxy-D-arabino-heptulosonate 7-P synthase | 4.1.2.15 | No hits | No hits |
| Â | 3-Dehydroquinate synthase | 4.2.3.4 | 2 | 2 |
| Â | 3-Dehydroquinate dehydratase | 4.2.1.10 | 2 | 2 |
| Â | Shikimate 5 dehydrogenase | 1.1.1.25 | 1 | 14 |
| Â | Shikimate kinase | 2.7.1.71 | 7 | 10 |
| Â | 5-Enolpyruvoylshikimate 3-P synthase | 2.5.1.19 | No hits | No hits |
| Â | Chorismate synthase | 4.2.3.5 | 2 | 2 |
| Â | Chorismate mutase | 5.4.99.5 | 1 | 1 |
| Â | Prephenate dehydratase | 4.2.1.51 | 3 | 5 |
| Â | Prephenate dehydrogenase | 1.3.1.12 | 2 (1) | 18 (2) |
| Â | Aromatic amino acid transaminase | 2.6.1.57 | 6 | 18 |
| Â | Anthranilate synthase | 4.1.3.27 | 6 (1) | 46 (29) |
| Â | Anthranilate phosphoribosyl transferase | 2.4.2.18 | 4 | 6 |
| Â | Phosphoribosylanthranilate synthase | 5.3.1.24 | No hits | No hits |
| Â | Indol-3-glycerol phosphate synthase | 4.1.1.48 | 4 (2) | 6 (2) |
| Â | Trp synthase | 4.2.1.20 | 8 (1) | 30 (1) |
| Â | Phe ammonia-lyase | 4.3.1.5 | 5 | 13 |
| Â | Cinnamate 4-hydroxilase | 1.14.13.11 | 1 | 3 |
| Â | 4-Coumarate coenzyme A ligase | 6.2.1.12 | 10 (1) | 40 (1) |
Flavonol biosynthesis | Naringenin chalcone synthase | 2.3.1.74 | 6 | 48 |
| Â | Chalcone isomerase | 5.5.1.6 | 3 | 17 |
| Â | Flavanone 3-hydroxylase | 1.14.11.9 | 2 (1) | 12 (1) |
| Â | Flavonol 3-hydroxylase | 1.14.13.21 | 6 | 7 |
| Â | Flavonol synthase | No E.C. | 2 | 19 |
| Â | Flavonol 3-O-glucosyltransferase | No E.C. | No hits | No hits |
Flavonoid biosynthetic pathway: anthocyanin biosynthesis | Dihydroflavonol 4-reductase | 1.1.1.219 | No hits | No hits |
| Â | Leucoanthocyanidin dioxygenase | NoE.C. | 2 | 33 |
| Â | UDP-flavonol 3-O-glucosyltransferase | 2.4.1.- | No hits | No hits |
| Â | Anthocyanin 5-O-glucosyltransferase | NoE.C. | 2 | 9 |
| Â | Anthocyanin 5-aromatic acyltransferase | 2.3.4.153 | 6 | 36 |
| Â | Anthocyanin permease | NoE.C. | No hits | No hits |
Proanthocyanidin biosynthesis | Anthocyanidin reductase | 1.3.1.77 | No hits | No hits |
| Â | Leucoanthocyanindin reductase | No E.C. | 2 (1) | 4 (2) |