Metabolism ofD- andL-[13C]alanine in rat liver detected by1H and13C NMR spectroscopyin vivo andin vitro

Looking at microbial metabolism by high-resolution 2 H-NMR spectroscopy

“…This reaction together with the reversed transformation of alanine to pyruvate is catalyzed by the alanine transaminase also known as alanine aminotransferase (Dolle, 2000; Yang et al, 2009). The activity of this enzyme combined with the protein degradation and membrane decomposition, together with the presence of some free alanine inside the cells give likely explanation for the moderate increase in the alanine signal in the spectra of rat liver homogenates during their long-term observation.…”

Enantiomer-specific selection of amino acids

“…Similar concepts may be applied to the physiological pathways regulating the higher preferences for L-alanine and L-serine over their D-isomers. 1 H and 13 C NMR spectroscopic studies upon infusion of L- and D-alanine labeled with 13 C in fasted rats show that D-alanine is metabolized significantly more slowly than the correspondingly labeled L-enantiomer (Dolle 2000). In addition, the immediate product of D-serine metabolism is likely to be hydroxypyruvate, rather than pyruvate, since hydroxypyruvate was identified as a metabolite of D,L-serine, but not of L-serine, in rat liver (Sprinson & Chargaff 1946; Nadkarni et al 1960).…”

Nuclear spin hyperpolarization of the solvent using signal amplification by reversible exchange (SABRE)

“…In the last few decades magnetic resonance (MR) techniques have greatly expanded our understanding of metabolism and metabolic flux [1–4]. A disadvantage of MR, however, has been its lack of sensitivity compared with other imaging modalities like optical, positron emission tomography (PET), and single-photon emission computed tomography (SPECT).…”