Standard Gibbs energy of metabolic reactions: VI. Glyceraldehyde 3-phosphate dehydrogenase reaction
| Autor: | Kristina Vogel, Christoph Held, Jan-Kristof Mühlenweg, Thomas Maskow, Gabriele Sadowski, Thorsten Greinert |
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| Rok vydání: | 2020 |
| Předmět: |
Activity coefficient
Work (thermodynamics) 010405 organic chemistry Chemistry General Chemical Engineering Enthalpy General Physics and Astronomy Thermodynamics 02 engineering and technology 01 natural sciences Standard enthalpy of formation 0104 chemical sciences Gibbs free energy symbols.namesake 020401 chemical engineering symbols Titration 0204 chemical engineering Physical and Theoretical Chemistry Chemical equilibrium Equilibrium constant |
| Zdroj: | Fluid Phase Equilibria. 517:112597 |
| ISSN: | 0378-3812 |
| DOI: | 10.1016/j.fluid.2020.112597 |
| Popis: | Glycolysis is a very central metabolic pathway for many organisms because it represents a key component in their energy production. For this reason, it has always been an extensively studied pathway. The glyceraldehyde 3-phosphate dehydrogenase (GDH) reaction is an important reaction of glycolysis yielding nicotinamide adenine dinucleotide (NADH). The aim of this work is to investigate the thermodynamics of the GDH reaction and determine the standard Gibbs energy of reaction Δ R g ' 0 and standard enthalpy of reaction Δ R h ' 0 . Currently, so-called ‘standard’ data exist in the literature that depend on the conditions they were measured at. In this work, Δ R g ' 0 and Δ R h ' 0 values were determined that are independent from reaction conditions by accounting for the activity coefficients of the reacting substances. Therefore, the equation of state electrolyte Perturbed-Chain Statistical Associating Fluid Theory (ePC-SAFT) was used. The required ePC-SAFT parameters were taken from literature or fitted to new experimental osmotic coefficients. A value of Δ R g ' 0 = 51.5 ± 0.4 kJ mol−1 was determined at 298.15 K. This value deviates by up to 10 kJ mol−1 from existing literature values, caused by activity coefficients in the reaction medium. It can be used to determine the Gibbs energy of reaction Δ R g ' , which will allow statements concerning the feasibility of the GDH reaction. Further, a method is presented to predict influences of pH, initial substrate concentration and Mg2+ concentration on the reaction equilibrium. Finally, we measured the standard reaction enthalpy for the GDH reaction Δ R h ' 0 by titration calorimetric measurements ( Δ R h ' 0 = 4.6 ± 0.1 kJ mol−1). This value was within van ’t Hoff evaluated Δ R h ' 0 (9 ± 16 kJ mol−1) using temperature-dependent equilibrium constants from equilibrium measurements corrected by ePC-SAFT predicted activity coefficients. |
| Databáze: | OpenAIRE |
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