TABLE 2.

15N enrichment in amino acids in bacteroids and the plant cytosol

Amino acidPlant cytosol Bacteroid
Mean APEaMean total amino acidbTotal amino acid (%)Mean APEMean total amino acidTotal amino acid (%)
Glutamate6.48 (±0.29)2,661.1 (±220.6)12.44.37 (±0.28)51.0 (±7.7)10.4
Alanine5.89 (±0.30)603.5 (±60.2)2.81.78 (±0.06)93.4 (±20.6)19.0
GABA4.31 (±0.43)497.4 (±32.8)2.34.52 (±0.34)7.9 (±2.0)1.6
Glutamine3.55 (±0.40)72.0 (±8.4)0.31.1 (±0.1)0.2
Proline1.07 (±0.54)71.4 (±5.0)0.30.50 (±0.67)3.4 (±0.5)0.7
Isoleucine1.06 (±0.23)216.2 (±35.6)1.00.84 (±0.21)20.8 (±6.1)4.2
Leucine1.02 (±0.23)254.5 (±41.8)1.20.79 (±0.21)24.5 (±7.2)5.0
Asparagine1.01 (±0.29)15,711.9 (±1,179.0)73.20.79 (±0.08)223.9 (±19.2)45.6
Phenylalanine0.94 (±0.89)232.5 (±24.1)1.12.68 (±0.85)8.2 (±2.5)1.7
Serine0.91 (±0.15)302.4 (±25.3)1.40.54 (±0.24)7.5 (±0.7)1.5
Glycine0.47 (±0.13)212.8 (±19.7)1.00.43 (±0.12)15.1 (±1.7)3.1
Valine0.31 (±0.16)197.1 (±22.7)0.90.33 (±0.38)10.5 (±2.7)2.1
Threonine0.26 (±0.21)156.0 (±8.8)0.7−0.16 (±0.20)5.8 (±0.9)1.2
β-Alanine0.24 (±0.33)101.4 (±7.7)0.50.65 (±0.23)5.8 (±1.3)1.2
Aspartate0.18 (±0.26)26.3 (±2.3)0.11.34 (±0.63)3.1 (±0.8)0.6
Tyrosine−0.53 (±0.35)162.8 (±17.4)0.80.41 (±0.83)9.2 (±2.5)1.9
Total21,479.3100491.2100
  • a The mean atom percent excess and standard error of the mean (shown in parentheses) from six experiments are shown.

  • b Total amino acids are given in nanomoles/gram of nodule (wet weight). The mean and standard error of the mean (shown in parentheses) from six experiments are shown.