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Metabolic impact of redox cofactor perturbations in Saccharomyces cerevisiae

Paper ID Volume ID Publish Year Pages File Format Full-Text
31785 44838 2009 9 PDF Available
Title
Metabolic impact of redox cofactor perturbations in Saccharomyces cerevisiae
Abstract

Redox cofactors play a pivotal role in coupling catabolism with anabolism and energy generation during metabolism. There exists a delicate balance in the intracellular level of these cofactors to ascertain an optimal metabolic output. Therefore, cofactors are emerging to be attractive targets to induce widespread changes in metabolism. We present a detailed analysis of the impact of perturbations in redox cofactors in the cytosol or mitochondria on glucose and energy metabolism in Saccharomyces cerevisiae to aid metabolic engineering decisions that involve cofactor engineering. We enhanced NADH oxidation by introducing NADH oxidase or alternative oxidase, its ATP-mediated conversion to NADPH using NADH kinase as well as the interconversion of NADH and NADPH independent of ATP by the soluble, non-proton-translocating bacterial transhydrogenase. Decreasing cytosolic NADH level lowered glycerol production, while decreasing mitochondrial NADH lowered ethanol production. However, when these reactions were coupled with NADPH production, the metabolic changes were more moderated. The direct consequence of these perturbations could be seen in the shift of the intracellular concentrations of the cofactors. The changes in product profile and intracellular metabolite levels were closely linked to the ATP requirement for biomass synthesis and the efficiency of oxidative phosphorylation, as estimated from a simple stoichiometric model. The results presented here will provide valuable insights for a quantitative understanding and prediction of cellular response to redox-based perturbations for metabolic engineering applications.

Keywords
Cofactor metabolism; Redox metabolism; Energy metabolism; Saccharomyces cerevisiae; Stoichiometric model
First Page Preview
Metabolic impact of redox cofactor perturbations in Saccharomyces cerevisiae
Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 11, Issues 4–5, July–September 2009, Pages 253–261
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering