Serial spectra were phase and baseline corrected and integrated using the XWinNMR software (Bruker Biospin, Coventry, UK). The integrated peak areas from the pyruvate/lactate experiments were plotted as a function of time, and apparent reaction rates were obtained by least-squares fitting of the data to the modified Bloch equations using a two-site exchange model as previously described (Hill et al, 2013a (link), 2013b (link)). All apparent rate constants for the forward reaction of conversion of pyruvate-to-lactate (kPL) are presented as a mean concentration per second normalised to the number of cells.