Separation of intra- and extracellular lactate NMR signals using a lanthanide shift reagent

This work describes the use of [Pr-DO3A] as a shift reagent for differentiating intra- and extracellular L-lactate resonance in (1)H- and (13)C-NMR spectra. DO3A acts as heptadentate ligand towards lanthanide(III) ions, leaving two coordination vacancies for the coordination of the L-lactate ion. The exchange between free and [Pr-DO3A]-bound L-lactate is fast on the NMR timescale, thus yielding a paramagnetically shifted L-lactate signal for the substrate in the compartment containing the paramagnetic chelate. The evaluation of the method was carried out on a model system based on sealed ghosts from human red blood cells.