Table 4.

Frequency of Correlations between Enzymes and Metabolites in the Same Metabolic Sequence

Total MatrixDefined Metabolic Segment
Number of Significant CorrelationsTotal No. of Metabolite-Enzyme Comparisons% of Significant CorrelationsNo. of Correlations between Enzymes and MetabolitesNo. of Possible Enzyme-Metabolite Pairs% of Significant Correlations
Calvin-Benson cycle and carbohydrates15200.20240
Starch synthesis01610020
Sucrose metabolism33470.9050
Hexose metabolism02970090
Nitrogen assimilation14210.20150
Aminotransferases030900100
Aromatic amino acid synthesis12720.4080
Malate and fumarate metabolism12600.4060
  • Several sets of enzymes and metabolites were identified in which the metabolites are the immediate or near-immediate substrates or products of enzymes: starch synthesis (pPGI, AGP, and starch), sucrose metabolism (cPGI, UGP, SPS, SuSy, INV, and sucrose), hexose metabolism (INV, GK, FK, sucrose, glucose, and fructose), nitrogen assimilation (NR, GS, GOGAT, NAD-IDH, NADP-ICDH and Gln, and 2-oxoglutarate and Glu), central amino transferase reactions (AspAT, AlaAT and Glu, 2-oxoglutarate, pyruvate, Asp, and Ala), aromatic amino acid synthesis (TK, shikimateDH, shikimate, Phe, Trp, and Tyr), and malate and fumarate metabolism (NAD-MDH, NADP-MDH, fumarase, malate, and fumarate). The six Calvin-Benson cycle enzymes were also compared with starch, sucrose, glucose, and fructose. For each set identified, all significant (pBH < 0.01) correlations were between enzyme-metabolite pairs in the trait set. This is compared with the number of correlations that these traits have in the data matrix without the initial activities.