Oxamate inhibits the conversion of glucose into several products of the tricarboxylic acid cycle, oxygen consumption and intracellular ATP. MDA-MB-231 cells were grown in medium containing 1 g/L [U-13C6]-glucose and exposed to either (a, c) PBS or (b, d) 40 mM oxamate. After 48 hours, live cells were washed, extracted with 10% trichloracetic acid (TCA), lyophilised and dissolved in 100% heavy water. The spectrum was recorded at 14.1 T with a recycle time of five seconds under standardised conditions of acquisition. 13C-isotopomers were quantified by indirect detection of protons in the 2D-NMR total correlation spectroscopy (TOCSY) spectrum. The four peaks representing the 13C-labelled glutamate/glutathione (Glu/GSH), alanine (Ala) and (a, b) lactate and (c, d) uridine bases are highlighted with red squares. Cells were cultured in the presence or absence of 40 mM oxamate for 24 hours and then (e) oxygen consumption was measured using an oxygen meter and (f) ATP concentration was determined with a luminometer as detailed. ATP standard curves were run concurrently. Data are plotted as the mean ± standard deviation.