INTRACELLULAR FLUX ANALYSIS IN HYBRIDOMAS USING MASS BALANCES AND IN-VITRO C-13 NMR

Intracellular fluxes are important in defining cellular physiology and its changes in response to environmental variations. Stoichiometric b alances combined with extracellular metabolite measurements were appli ed to the estimation of intracellular fluxes and the study of energy m etabolism in the hybridoma cell line ATCC CRL 1606. Redundant measurem ents allowed the evaluation of the consistency of the stoichiometry, m easurements, and pseudo-steady-state assumption leading to refinement of the assumed biochemistry and identification of measurement errors. To validate the flux estimates, two batch experiments were performed w ith glucose labeled in the 1 position with C-13. The distribution of C -13 in secreted lactate was measured via nuclear magnetic resonance sp ectroscopy (NMR) and compared to that predicted from the estimated int racellular fluxes. There was good agreement between the measured and e stimated isotope distributions, demonstrating the validity of the flux estimates obtained from stoichiometric balances. (C) 1995 John Wiley and Sons, Inc.