In systems biology, material balances, kinetic models, and thermodynamic boundary
conditions are increasingly used for metabolic network analysis. It is remarkable that the reversibility
of enzyme-catalyzed reactions and the influence of cytosolic conditions are often neglected in kinetic
models. In fact, enzyme-catalyzed reactions in numerous metabolic pathways such as in glycolysis are
often reversible, i.e., they only proceed until an equilibrium state is reached and not until the substrate
is completely consumed. Here, we propose the use of irreversible thermodynamics to describe
the kinetic approximation to the equilibrium state in a consistent way with very few adjustable
parameters. Using a flux-force approach allowed describing the influence of cytosolic conditions
on the kinetics by only one single parameter. The approach was applied to reaction steps 2 and
9 of glycolysis (i.e., the phosphoglucose isomerase reaction from glucose 6-phosphate to fructose
6-phosphate and the enolase-catalyzed reaction from 2-phosphoglycerate to phosphoenolpyruvate
and water). The temperature dependence of the kinetic parameter fulfills the Arrhenius relation
and the derived activation energies are plausible. All the data obtained in this work were measured
efficiently and accurately by means of isothermal titration calorimetry (ITC). The combination of
calorimetric monitoring with simple flux-force relations has the potential for adequate consideration
of cytosolic conditions in a simple manner.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:88929 |
| Date | 10 January 2024 |
| Creators | Vogel, Kristina, Greinert, Thorsten, Reichard, Monique, Held, Christoph, Harms, Hauke, Maskow, Thomas |
| Publisher | MDPI |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8341, 10.3390/ijms21218341 |
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