C-13 isotopomer analysis of glutamate by J-resolved heteronuclear single quantum coherence spectroscopy

C-13 NMR isotopomer analysis is a powerful method for measuring metabolic f luxes through pathways intersecting in the tricarboxylic acid cycle. Howeve r, the inherent insensitivity of C-13 NMR spectroscopy makes application of isotopomer analysis to small tissue samples (mouse tissue, human biopsies, or cells grown in tissue culture) problematic. H-1 NMR is intrinsically mo re sensitive than C-13 NMR and can potentially supply the same information via indirect detection of C-13 providing that isotopomer information can be preserved. We report here the use of J-resolved HSQC (J-HSQC) for C-13 iso topomer analysis of tissue samples. We show that J-HSQC reports isotopomer multiplet patterns identical to those reported by direct C-13 detection but with improved sensitivity. (C) 2001 Academic Press.