13C NMR study of the generation of C2- and C3,-deuterated lactic acid by tumoral pancreatic islet cells exposed to D-[1-13C]-, D-[2-13C]- and D-[6-13C]-Glucose in 2H2O

✍ Scribed by Rudolph Willem; Monique Biesemans; François Kayser; Professor; Dr. Willy J. Malaise

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 918 KB
• Volume: 31
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910310304

✦ Synopsis

Abstract

Tumoral pancreatic islet cells of the RIN5mF line were incubated for 120 min in media prepared in ^2^H~2~O and containing D‐[1‐^13^C]glucose, and D‐[2‐^13^C]glucose, and D‐[6‐^13^C]glucose. The generation of C~2~‐ and C~3~‐ deuterated lactic acid was assessed by ^13^C NMR. The interpretation of experimental results suggests that a) the efficiency of deuteration on the C~1~ of D‐fructose 6‐phosphate does not exceed about 47% and 4% in the phosphoglucoisomerase and phosphomannoisomerase reactions, respectively; b) approximately 38% of the molecules of D‐glyceraldehyde 3‐phosphate generated from D‐glucose escape deuteration in the sequence of reactions catalyzed by triose phosphate isomerase and aldolase; and c) about 41% of the molecules of pyruvate generated by glycolysis are immediately converted to lactate, the remaining 59% of pyruvate molecules undergoing first a single or double back‐and‐forth interconversion with L‐alanine. It is proposed that this methodological approach, based on high resolution ^13^C NMR spectroscopy, may provide novel information on the regulation of back‐and‐forth interconversion of glycolytic intermediates in intact cells as modulated, for instance, by enzyme‐to‐enzyme tunneling.