Table 5.
MID and average labeling abundance (%) per carbon of free amino acids
| Amino acids | Mass isotopomers | Average labeling (% 13C abundance) | |
|---|---|---|---|
| [13C]GLC | [13C]Gln | ||
| Arg | M+0 | 64.38±0.63 | 6.25±0.49 |
| M+1 | 24.60±0.99 | 2.92±0.39 | |
| M+2 | 5.90±0.50 | 2.25±0.66 | |
| M+3 | 2.88±0.55 | 6.73±0.35 | |
| M+4 | 1.44±0.47 | 4.80±0.29 | |
| M+5 | 0.69±0.32 | 59.45±1.85 | |
| M+6 | 0.11±0.27 | 18.24±1.97 | |
| Asn | M+0 | 57.28±0.49 | 30.86±0.90 |
| M+1 | 12.94±1.21 | 10.26±1.93 | |
| M+2 | 15.90±1.26 | 16.68±1.71 | |
| M+3 | 10.27±1.74 | 12.74±1.87 | |
| M+4 | 3.74±0.69 | 30.01±1.04 | |
| Glu* | M+0 | 46.92±0.50 | 12.67±0.81 |
| M+1 | 11.64±1.25 | 3.18±0.54 | |
| M+2 | 21.08±1.45 | 4.70±0.83 | |
| M+3 | 10.66±3.19 | 12.09±0.92 | |
| M+4 | 7.60±0.43 | 5.48±0.59 | |
| M+5 | 2.11±0.59 | 61.88±2.23 | |
| Gln | M+0 | 89.70±0.61 | 4.24±0.73 |
| M+1 | 3.72±2.13 | 0.31±0.32 | |
| M+2 | 4.87±3.49 | 4.23±1.52 | |
| M+3 | 0.76±0.86 | 0.05±0.25 | |
| M+4 | 0.56±0.61 | 1.81±0.65 | |
| M+5 | 0.40±0.31 | 90.81±2.03 | |
| Gly | M+0 | 60.63±2.35 | 79.20±4.45 |
| M+1 | 26.80±1.43 | 7.15±3.41 | |
| M+2 | 12.80±1.37 | 11.05±2.41 | |
| C1-Gly | M+0 | 81.13±1.86 | 81.61±1.32 |
| M+1 | 18.87±1.86 | 18.39±1.32 | |
| His | M+0 | 6.82±0.92 | 90.66±0.47 |
| M+1 | 13.23±0.95 | 8.22±0.66 | |
| M+2 | 21.25±0.94 | 0.08±0.63 | |
| M+3 | 21.84±1.01 | 0.31±0.59 | |
| M+4 | 15.85±1.21 | 0.25±0.33 | |
| M+5 | 14.83±1.18 | 0.31±0.63 | |
| M+6 | 6.10±0.87 | 0.15±0.38 | |
| C1-His | M+0 | 53.12±0.44 | 98.03±0.80 |
| M+1 | 46.88±0.44 | 1.97±0.80 | |
| Ile | M+0 | 33.36±3.69 | 34.92±3.53 |
| M+1 | 10.26±1.30 | 11.22±2.07 | |
| M+2 | 30.39±2.06 | 7.01±1.99 | |
| M+3 | 11.16±3.29 | 9.00±3.93 | |
| M+4 | 9.60±2.56 | 34.13±2.76 | |
| M+5 | 4.17±1.67 | 2.11±2.19 | |
| M+6 | 1.09±0.69 | 1.64±0.50 | |
| C1-Ile | M+0 | 84.86±2.41 | 57.80±1.67 |
| M+1 | 15.14±2.41 | 42.21±1.67 | |
| Met | M+0 | 28.57±2.62 | 37.05±0.73 |
| M+1 | 32.62±2.02 | 10.90±0.87 | |
| M+2 | 15.34±1.01 | 7.75±1.07 | |
| M+3 | 14.51±1.55 | 20.44±1.22 | |
| M+4 | 7.70±0.35 | 24.98±1.52 | |
| M+5 | 1.75±0.78 | 0.09±0.47 | |
| C1-Met | M+0 | 75.44±1.48 | 53.35±0.99 |
| M+1 | 24.56±1.48 | 46.65±0.99 | |
| Phe | M+0 | 9.15±0.81 | 88.70±0.48 |
| M+1 | 5.59±0.29 | 10.22±0.38 | |
| M+2 | 15.22±0.68 | 0.58±0.36 | |
| M+3 | 15.63±0.59 | 0.41±0.39 | |
| M+4 | 16.76±0.60 | 0.05±0.29 | |
| M+5 | 15.75±0.33 | 0.00±0.26 | |
| M+6 | 10.90±0.62 | 0.00±0.26 | |
| M+7 | 6.17±0.27 | 0.01±0.25 | |
| M+8 | 3.73±0.36 | 0.03±0.26 | |
| M+9 | 1.13±0.27 | 0.00±0.25 | |
| C1-Phe | M+0 | 71.46±0.52 | 97.90±0.37 |
| M+1 | 28.54±0.52 | 2.11±0.37 | |
| Ser* | M+0 | 32.66±2.55 | 81.28±2.31 |
| M+1 | 18.70±4.96 | 10.75±5.03 | |
| M+2 | 29.99±3.72 | 1.43±5.82 | |
| M+3 | 18.66±8.72 | 6.55±3.85 | |
| Val | M+0 | 17.35±0.51 | 79.76±1.13 |
| M+1 | 7.55±0.36 | 7.29±0.33 | |
| M+2 | 32.43±0.63 | 5.44±0.78 | |
| M+3 | 16.37±0.39 | 6.87±0.64 | |
| M+4 | 16.22±0.56 | 0.32±0.30 | |
| M+5 | 10.25±0.38 | 0.33±0.30 | |
| C1-Val | M+0 | 70.32±0.36 | 89.95±0.78 |
| M+1 | 29.68±0.36 | 10.05±0.78 | |
Each mass isotopomer was detected and measured through LC-MS/MS in a positive ion mode. MID and the average labeling abundance (%) in each carbon were determined for free amino acids from [13C]GLC and [13C]Gln. The values listed are the average of three biological replicates ±SD. Labeling of carboxyl fragments resulting from LC-MS/MS analysis is included as ‘C1’ of the corresponding amino acid. An asterisk (*) indicates an amino acid whose MID values were corrected using the dilution factor from the 20% labeling experiment (Supplementary Table S6).