The chemical deuteration laboratory at ESS recently produced its first chemically deuterated molecule, sodium pyruvate-d3. It was produced by reacting pyruvic acid with deuterium oxide (D2O) and sodium bicarbonate:
Sodium pyruvate-d3 was analysed by nuclear magnetic resonance (NMR) spectroscopy to determine the identity and purity of the molecule, and to quantify the deuteration at each carbon atom. From the 13C NMR spectrum, it was observed that the sample was highly deuterated, and that the integrity of the sample was maintained.
13C NMR spectrum showing a pattern indicative of deuteration at a carbon atom (25 ppm).
The high deuteration level was confirmed by mass spectrometry, with a peak observed at the value expected (90.0 atomic mass units).
Mass spectrum showing the a signal at the expected atomic mass for pyruvate-d3 (90.0 amu), shifted by three atomic mass units from pyruvate (87.0 amu), which is consistent with the exchange of three 1H atoms for three 2H atoms.
The pyruvate ion (CH3COCOO–) plays an important biochemical role, providing energy to cell via a series of chemical reactions known as the Krebs cycle. It is also a substrate for the lactate dehydrogenase enzyme, from which lactic acid is produced during normal metabolism and exercise. For the chemical deuteration laboratory, sodium pyruvate-d3 will serve as a precursor to deuterated lactic acid-d4. Lactic acid-d4 is a chiral molecule and so exists in two forms, D-lactic acid-d4 and L-lactic acid-d4; the use of an enzyme to produce lactic acid-d4 from sodium pyruvate-d3 will allow us to produce one or the other, instead of a mixture of both would have to be separated.