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Flux balance analysis of CHO cells before and after a metabolic switch from lactate production to consumption

Authors

  • Verónica S. Martínez,

    1. Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; telephone: +61 7 3346 3986; fax: +61 7 3346 3973
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  • Stefanie Dietmair,

    1. Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; telephone: +61 7 3346 3986; fax: +61 7 3346 3973
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  • Lake-Ee Quek,

    1. Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; telephone: +61 7 3346 3986; fax: +61 7 3346 3973
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  • Mark P. Hodson,

    1. Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; telephone: +61 7 3346 3986; fax: +61 7 3346 3973
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  • Peter Gray,

    1. Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; telephone: +61 7 3346 3986; fax: +61 7 3346 3973
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  • Lars K. Nielsen

    Corresponding author
    1. Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; telephone: +61 7 3346 3986; fax: +61 7 3346 3973
    • Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; telephone: +61 7 3346 3986; fax: +61 7 3346 3973
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  • Verónica S. Martínez and Stefanie Dietmair contributed equally to this work.

Abstract

Mammalian cell cultures typically exhibit an energy inefficient phenotype characterized by the consumption of large quantities of glucose and the concomitant production of large quantities of lactate. Under certain conditions, mammalian cells can switch to a more energy efficient state during which lactate is consumed. Using a metabolic model derived from a mouse genome scale model we performed flux balance analysis of Chinese hamster ovary cells before and after a metabolic switch from lactate production (in the presence of glucose) to lactate consumption (after glucose depletion). Despite a residual degree of freedom after accounting for measurements, the calculated flux ranges and associated errors were narrow enough to enable investigation of metabolic changes across the metabolic switch. Surprisingly, the fluxes through the lower part of the TCA cycle from oxoglutarate to malate were very similar (around 60 µmol/gDW/h) for both phases. A detailed analysis of the energy metabolism showed that cells consuming lactate have an energy efficiency (total ATP produced per total C-mol substrate consumed) six times greater than lactate producing cells. Biotechnol. Bioeng. 2013; 110: 660–666. © 2012 Wiley Periodicals, Inc.

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