pH sensitivity of carbon dioxide conversion catalyzed by isocitrate dehydrogenase

Abstract

Biological conversion of carbon dioxide has been examined with growing interest in recent years for its potential in reduction of greenhouse gas emission. While many conversion routes have been suggested and demonstrated, understanding the constraints and limits of such reaction routes, either in vivo or in vitro, is becoming increasingly important. The current work examines the pH sensitivity of the reaction catalyzed by isocitrate dehydrogenase with respect to its potentials in carbon capture and conversion via both experimental measurements and theoretical analysis. As a result, the reaction equilibrium constant determined experimentally shifted by a factor of approximate to 500-fold when pH changed between 5 and 9. Thermodynamic analysis agreed well with such a pH sensitivity, indicating the impact of pH on Gibbs free energy of the species involved in the reaction helped to shift the reaction equilibrium.