TABLE I. Isotope labeling measurements used for metabolic flux determination.
(a) LC-MS/MS ions and (b) GC-MS ions used to assess metabolite labeling. Standard errors of measurement (SEM) were determined based on the lack of agreement between measured and theoretically computed mass isotopomer distributions obtained from unlabeled cell extracts.
(a) LC-MS/MS ions | |||||
---|---|---|---|---|---|
Metabolite | Mass | Carbons | Composition | SEM | Reference |
3PGA | 185 | 1-2-3 | C3H6O7P | 0.5 | (Luo et al., 2007) |
DHAP | 169 | 1-2-3 | C3H6O6P | 1.3 | Ibid. |
F6P | 259 | 1-2-3-4-5-6 | C6H12O9P | 1.7 | Ibid. |
G6P | 259 | 1-2-3-4-5-6 | C6H12O9P | 1.4 | Ibid. |
GAP | 169 | 1-2-3 | C3H6O6P | 1.3 | Ibid. |
PEP | 167 | 1-2-3 | C3H4O6P | 0.5 | Ibid. |
R5P | 229 | 1-2-3-4-5 | C5H10O8P | 1.5 | Ibid. |
RUBP | 309 | 1-2-3-4-5 | C5H11O11P2 | 0.7 | Ibid. |
S7P | 289 | 1-2-3-4-5-6-7 | C7H14O10P | 2.8 | Ibid. |
RU5P | 229 | 1-2-3-4-5 | C5H10O8P | 1.3 | Ibid. |
(b) GC-MS ions | |||||
Metabolite | Mass | Carbons | Composition | SEM | Reference |
3PGA | 357 | 2-3 | C11H30O5PSi3 | 1.0 | (Kitson et al., 1996) |
3PGA | 459 | 1-2-3 | C14H36O7PSi4 | 1.0 | Ibid. |
CIT | 273 | 1-2-3-4-5 | C11H21O4Si2 | 1.0 | (Tisza, 1994) |
CIT | 363 | 1-2-3-4-5 | C14H31O5Si3 | 1.0 | Ibid. |
CIT | 375 | 1-2-3-4-5-6 | C14H27O6Si3 | 1.6 | (Huege et al., 2007) |
CIT | 465 | 1-2-3-4-5-6 | C17H37O7Si4 | 1.1 | Ibid. |
FUM | 245 | 1-2-3-4 | C9H17O4Si2 | 1.0 | Ibid. |
GA | 292 | 1-2 | C11H28O3Si3 | 1.0 | (Petersson, 1970) |
GA | 307 | 1-2-3 | C11H27O4Si3 | 1.3 | (Huege et al., 2007) |
MAL | 233 | 2-3-4 | C9H21O3Si2 | 1.0 | (Petersson, 1972) |
SUC | 247 | 1-2-3-4 | C9H19O4Si2 | 1.0 | (Huege et al., 2007) |