Multiple bond 13C-13C spin-spin coupling provides complementary information in a 13C NMR isotopomer analysis of glutamate.
Most 13C nuclear magnetic resonance (NMR) isotopomer analyses relate a metabolic index of interest to populations of 13C isotopomers as reported by one-bond 13C-13C spin-spin couplings. Metabolic conditions that produce highly enriched citric acid cycle intermediates often lead to 13C NMR spectra of metabolites such as glutamate that show extra multiplets due to long-range couplings. It can be demonstrated from 13C NMR spectra of hearts perfused with mixtures of acetate plus propionate that multiplets in glutamate C2 arising from 3J25 coupling provide a direct readout of acetyl-CoA fractional enrichment (FC1 and FC3), while multiplets in glutamate C5 arising from 2J35 and 3J25 couplings quantitatively reflect enrichment of the anaplerotic substrate.
Department of Biochemistry and Center of Neurosciences, University of Coimbra, Portugal.
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Carvalho
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Babcock
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FM
Jeffrey
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Sherry
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Malloy
D002247:Carbon Isotopes; D005583:Fourier Analysis; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D009206:Myocardium / Q000378:metabolism*; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013113:Spin Labels
D002247:Carbon Isotopes; D013113:Spin Labels; D018698:Glutamic Acid