Galazzo1990_FermentationPathwayKinetics

This a model from the article:

Fermentation pathway kinetics and metabolic flux control in suspended and immobilized Saccharomyces cerevisiae

Jorge L. Galazzo and James E. Bailey
Enzyme and Microbial TechnologyVolume 12, Issue 3, 1990, Pages 162-172.

DOI:10.1016/0141-0229(90)90033-M

Abstract:

Measurements of rates of glucose uptake and of glycerol and ethanol formation combined with knowledge of the metabolic pathways involved in S. cerevisiae were employed to obtain in vivo rates of reaction catalysed by pathway enzymes for suspended and alginate-entrapped cells at pH 4.5 and 5.5. Intracellular concentrations of substrates and effectors for most key pathway enzymes were estimated from in vivo phosphorus-31 nuclear magnetic resonance measurements. These data show the validity in vivo of kinetic models previously proposed for phosphofructokinase and pyruvate kinase based on in vitro studies. Kinetic representations of hexokinase, glycogen synthetase, and glyceraldehyde 3-phosphate dehydrogenase, which incorporate major regulatory properties of these enzymes, are all consistent with the in vivo data. This detailed model of pathway kinetics and these data on intracellular metabolite concentrations allow evaluation of flux-control coefficients for all key enzymes involved in glucose catabolism under the four different cell environments examined. This analysis indicates that alginate entrapment increases the glucose uptake rate and shifts the step most influencing ethanol production from glucose uptake to phosphofructokinase. The rate of ATP utilization in these nongrowing cells strongly limits ethanol production at pH 5.5 but is relatively insignificant at pH 4.5.

SBML level 2 code generated for the JWS Online project by Jacky Snoep using

PySCeS

Run this model online at
http://jjj.biochem.sun.ac.za

To cite JWS Online please refer to: Olivier, B.G. and Snoep, J.L. (2004)
Web-based
modelling using JWS Online, Bioinformatics, 20:2143-2144

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Biomodels Curation: The model reproduces Fig 2 of the paper. However, it appears that the figures are swapped, hence the plot for V/Vmax vs Glucose actually represnts V/Vmax vs ATP and the vice versa is true for the other figure. The rate of hexokinase reaction that is obtained upon simulation of the model is 17.24 mM/min, therefore V/Vmax has a value of 17.24/68.5=0.25. For steady state values of Glucose and ATP (0.038 and 1.213 mM respectively), the V/Vmax values correctly correspond to 0.25, if we were to assume that the figures are swapped.

BioModels Curation updated on 25th November 2010: Figure 3 of the reference publication has been reproduced and added as a curation figure for the model.
This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2011 The BioModels.net Team.
For more information see the terms of use.
To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.