A Method for Obtaining 13C Isotopomer Populations in 13C-Enriched Glucose

✍ Scribed by J.G. Jones; G.L. Cottam; B.C. Miller; A.D. Sherry; C.R. Malloy

• Book ID: 102558184
• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 364 KB
• Volume: 217
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1006/abio.1994.1095

✦ Synopsis

({ }^{13} \mathrm{C}) NMR analysis of ({ }^{13} \mathrm{C})-enriched glucose containing multiple isotopomers is hampered by chemical shift similarities of several carbon resonances and by the presence of two anomeric forms. A convenient and quantitative method of enzymatically oxidizing glucose to gluconate in tissue and perfusate extracts is presented. The six carbon resonances of the resulting ({ }^{13} \mathrm{C})-enriched gluconate are fully resolved at high (\mathrm{pH}), thereby allowing a determination of the fractional population of each ({ }^{13} \mathrm{C}) isotopomer by ({ }^{13} \mathrm{C}) NMR. The utility of this method is demonstrated using the effluent from an isolated perfused liver containing ({ }^{13} \mathrm{C})-enriched glucose produced by hepatic metabolism of sodium (\left[1,2,3-{ }^{13} \mathrm{C}_{3}\right]) propionate via the citric acid cycle and gluconeogenesis. An analysis of the gluconate (\mathrm{C} 2) and (\mathrm{C5}) resonances in this sample showed that pentose phosphate activity was insignifcant during this perfusion protocol. As demonstrated, this method provides a means of fully describing ({ }^{13} \mathrm{C}) isotopomer populations in enriched glucose samples where isotope may be derived from multiple metabolic pathways, thus expanding the scope of experimental design and enrichment strategies. C 1804 Academic Press, Inc.