We have applied Metabolic Control Analysis (MCA) in an attempt to determine the distribution of glycolytic flux control between the steps of glycolysis in aged disks of potato tuber under aerobic conditions, using concentrations of glycolytic metabolites in tuber tissue from a range of transgenic potato plants and published enzyme kinetic data. We modelled the substrate and effector kinetics of potato tuber phosphofructokinase (PFK) by reanalysing published results. Despite the scarcity of reliable kinetic data, our results are in agreement with experimental findings namely that, under the conditions described, PFK has little control over glycolytic flux. Furthermore our analysis predicts that under these conditions far more control lies in the dephosphorylation of phosphoenolpyruvate and/or in the steps beyond. We have validated the results of our analysis in two ways. First, predictions based on calculated concentration control coefficients from the analysis show generally good agreement with observed metabolite deviation indices discussed in the preceding paper [Thomas, Mooney, Burrell, and Fell (1997) Biochem. J.322, 111Ő117]. Second, sensitivity analysis of our results shows that the calculated control coefficients are robust to errors in the elasticities used in the analysis, of which relatively few need to be known accurately. Experimental and control analysis results agree with previous predictions of MCA that strong co-operative feedback inhibition of enzymes serves to move flux control downstream of the inhibiting metabolite. We conclude that MCA can successfully model the outcome of experiments in the genetic manipulation of enzyme amounts.
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Research Article|
February 15 1997
Metabolic Control Analysis of glycolysis in tuber tissue of potato (Solanum tuberosum): explanation for the low control coefficient of phosphofructokinase over respiratory flux
Simon THOMAS;
Simon THOMAS
*School of Biological and Molecular Sciences, Oxford Brookes University, Oxford OX3 0BP, U.K.
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Peter J. F. MOONEY;
Peter J. F. MOONEY
†Advanced Technologies (Cambridge) Ltd., 210 Cambridge Science Park, Cambridge CB4 4WA, U.K.
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Michael M. BURRELL;
Michael M. BURRELL
†Advanced Technologies (Cambridge) Ltd., 210 Cambridge Science Park, Cambridge CB4 4WA, U.K.
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David A. FELL
David A. FELL
‡
*School of Biological and Molecular Sciences, Oxford Brookes University, Oxford OX3 0BP, U.K.
‡To whom correspondence should be addressed.
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Publisher: Portland Press Ltd
Received:
July 04 1996
Revision Received:
October 01 1996
Accepted:
October 14 1996
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 1997
1997
Biochem J (1997) 322 (1): 119–127.
Article history
Received:
July 04 1996
Revision Received:
October 01 1996
Accepted:
October 14 1996
Citation
Simon THOMAS, Peter J. F. MOONEY, Michael M. BURRELL, David A. FELL; Metabolic Control Analysis of glycolysis in tuber tissue of potato (Solanum tuberosum): explanation for the low control coefficient of phosphofructokinase over respiratory flux. Biochem J 15 February 1997; 322 (1): 119–127. doi: https://doi.org/10.1042/bj3220119
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