Enrique Meléndez-Hevia

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A method for determining Control Coefficients is proposed for systems studied in vitro and applied to a model pathway. Rat liver extract, which converts glucose into glycerol 3-phosphate, was used with the addition to the incubation mixture of fructose-bisphosphate aldolase, triose-phosphate isomerase and glycerol-3-phosphate dehydrogenase as 'auxiliary'(More)
Sugar rearrangement in the pentose phosphate cycle for transformation of six pentoses into five hexoses is analysed by abstraction to a mathematical model consisting of the resolution of a logical mathematical game of optimization. In the model, the problem is to arrive at five boxes containing six balls each, having started with six boxes containing five(More)
The evolutionary origin of the Krebs citric acid cycle has been for a long time a model case in the understanding of the origin and evolution of metabolic pathways: How can the emergence of such a complex pathway be explained? A number of speculative studies have been carried out that have reached the conclusion that the Krebs cycle evolved from pathways(More)
Optimization of molecular design in cellular metabolism is a necessary condition for guaranteeing a good structure-function relationship. We have studied this feature in the design of glycogen by means of the mathematical model previously presented that describes glycogen structure and its optimization function [Meléndez-Hevia et al. (1993), Biochem J 295:(More)
In the first part of this work [Heinrich, R., Montero, F., Klipp, E., Waddell, T. G. & Melendez-Hevia, E. (1997) Eur. J. Biochem. 243, 191-201] the kinetic and thermodynamic constraints under which an optimal glycolysis must be designed have been analysed. In this second part, we present a chemical analysis of the glycolytic pathway in order to determine if(More)
Control of flux and transition time was investigated with a reconstructed rabbit muscle glycolytic system in vitro as an experimental model. The results show agreement with the summation property for the Flux Control Coefficients [Kacser & Burns (1973) Symp. Soc. Exp. Biol. 27, 65-104; Heinrich & Rapoport (1974) Eur. J. Biochem. 42, 89-95]. Control of flux(More)
The structural properties of carbohydrate metabolism are being studied. The present contribution focuses mainly on those processes involving the transfer of carbon fragments among sugars. It is shown how enzymatic activities fix the way the system self-organizes stoichiometrically at the steady state. It is proven that there exists a specific correspondence(More)
The animal glycogen molecule has to be designed in accordance with its metabolic function as a very effective fuel store allowing quick release of large amounts of glucose. In addition, the design should account for a high capacity of glucose storage in the least possible space. We have studied the optimization of these variables by means of a mathematical(More)
Sugar rearrangement in the pentose phosphate cycle and other related pathways were previously analysed by abstraction to a mathematical game of optimization based on certain hypotheses concerning enzymatic mechanisms of living cells (Meléndez-Hevia & Isidoro, 1985, J. theor. Biol. 117, 251-263). The solution of that problem shows that the metabolic pathway,(More)
It is analyzed whether the structural design of contemporary glycolysis can be explained theoretically on the basis of optimization principles originating from natural selection during evolution. Particular attention is paid to the problem of how the kinetic and thermodynamic properties of the glycolytic pathway are related to its stoichiometry with respect(More)