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.
Carvalho
R A
RA
Department of Biochemistry and Center of Neurosciences, University of Coimbra, Portugal.
Babcock
E E
EE
Jeffrey
F M
FM
Sherry
A D
AD
Malloy
C R
CR
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