The thermodynamic equilibrium of the aminotransferase reaction from L-alanine and 2-oxoglutarate to Lglutamate and pyruvate in aqueous solution was investigated in a temperature range between 25 and 37 C and pH between at 5 and 9. Prior to considering the reaction equilibria, measurements were carried out to ensure the enzyme activity in the aqueous reaction media. After that, equilibrium concentrations of reacting agents were measured by HPLC-analysis. At constant temperature and pH, reaction equilibriumwas shown to depend on the absolute molalities (0.005e0.130 mol kg 1) as well as on the ratio of initial molalities of the reactants. It could be concluded that reaction equilibrium was shifted towards the product site upon increasing reactant molalities, increasing temperature, and increasing pH. Further, yields of pyruvate were increased upon excess initial molality of L-alanine compared to 2-oxoglutarate. The thermodynamic equilibrium constant Ka* was determined by extrapolating the ratio of product equilibrium molalites and reactant equilibrium molalites to infinite dilution of all reacting agents. The activity-coefficient ratio of products and reactants in the reaction media was predicted with ePC-SAFT. Combining Ka* and the activity-coefficient ratio allowed quantitatively predicting the influence of temperature, pH, and reacting-agent molalities on the reaction equilibrium.
Compounds
#
Formula
Name
1
C3H3NaO3
sodium pyruvate
2
C5H8NNaO4
sodium (S)-2-amino-4-carboxybutanoate
3
C5H4Na2O5
disodium 2-oxo-glutarate
4
H2O
water
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.