Spectral analysis of ¹H coupled ¹³C spectra of the amino acids: Adaptive spectral library of amino acid ¹³C isotopomers and positional fractional ¹³C enrichments

The natural abundance ¹H‐coupled ¹³C NMR spectra of all proteogenic amino acids were measured in D₂O at pH* 1. The accurate ¹H,¹³C spin‐spin coupling constants were analyzed using total‐line‐shape fitting. The obtained spectral parameters can be used to establish a spectral library of amino acid ¹³C isotopomers. The adaptive spectral library principle is introduced and discussed in this article. The simulated spectra can be applied to quantification of ¹³C isotopomer mixtures of amino acids and, thus, for exploring metabolic pathways. Also a protocol for amino acid ¹³C isotopomer metabolomic profiling in ¹³C labeled glucose feeding experiments is outlined. The approach is suggested to give invaluable information about positional fractional ¹³C enrichments, which are not easily available by any other method.