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Table 7 Accounting for the isotopic effect in data correction for C2-C4 and C2-C5 fragments of glutamine using the factor of 0.6 for the labeled isotopomers

From: MIDcor, an R-program for deciphering mass interferences in mass spectra of metabolites enriched in stable isotopes

13C-labeling m0 m1 m2 m3 m4 fragment
natural 1 0 0 0 0 C2C4
natural 1 0 0 0 0 C2C5
3-13C-Gln 0.008 0.986 0.0 0.005 0 C2C4
3-13C-Gln 0.005 0.9895 0.001 0.003 0.001 C2C5
U-13C-Gln 0.004 0.005 0.018 0.973 0 C2C4
U-13C-Gln 0.003 0.003 0.01 0.022 0.959 C2C5
n:3:U_90:2:8 0.889 0.020 0.002 0.089 0 C2C4
n:3:U_90:2:8 0.888 0.021 0.001 0.002 0.088 C2C5
n:3:U_40:30:30 0.437 0.277 0.006 0.280 0 C2C4
n:3:U_40:30:30 0.436 0.277 0.003 0.007 0.276 C2C5
n:3:U_95:2:3 0.940 0.026 0.001 0.032 0.0 C2C4
n:3:U_95:2:3 0.940 0.027 0.0 0.001 0.032 C2C5
  1. The calculated artificial labeling of naturally or artificially 13C labeled C2–C4 and C2–C5 fragments of glutamine was obtained by applying the algorithm modified to account for the isotopic effect. The samples were prepared either from unlabeled glutamine (natural), 13C- glutamine labeled at position 3 (3-13C-Gln), uniformly labeled glutamine (U-13C-Gln), or various ratios of these samples: natural : 3-13C-Gln : U-13C-Gln (n:3:U) as indicated