For systems biology, it is important to describe the kinetic and thermodynamic properties
of enzyme-catalyzed reactions and reaction cascades quantitatively under conditions prevailing in the
cytoplasm. While in part I kinetic models based on irreversible thermodynamics were tested, here in
part II, the influence of the presumably most important cytosolic factors was investigated using two
glycolytic reactions (i.e., the phosphoglucose isomerase reaction (PGI) with a uni-uni-mechanism
and the enolase reaction with an uni-bi-mechanism) as examples. Crowding by macromolecules
was simulated using polyethylene glycol (PEG) and bovine serum albumin (BSA). The reactions
were monitored calorimetrically and the equilibrium concentrations were evaluated using the
equation of state ePC-SAFT. The pH and the crowding agents had the greatest influence on the
reaction enthalpy change. Two kinetic models based on irreversible thermodynamics (i.e., single
parameter flux-force and two-parameter Noor model) were applied to investigate the influence of
cytosolic conditions. The flux-force model describes the influence of cytosolic conditions on reaction
kinetics best. Concentrations of magnesium ions and crowding agents had the greatest influence,
while temperature and pH-value had a medium influence on the kinetic parameters. With this
contribution, we show that the interplay of thermodynamic modeling and calorimetric process
monitoring allows a fast and reliable quantification of the influence of cytosolic conditions on kinetic
and thermodynamic parameters.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:88933 |
| 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 | 7921, 10.3390/ijms21217921 |
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