Photocatalytic fixation of carbon dioxide in oxoglutaric acid using isocitrate dehydrogenase and cadmium sulphide

Abstract

Photocatalytic fixation of CO₂ in oxoglutaric acid to yield isocitric acid was investigated with the use of isocitrate dehydrogenase as a catalyst, methyl viologen as an electron mediator and cadmium sulphide as a photocatalyst. The rate of the isocitric acid production depended on the concentration of oxoglutaric acid and methyl viologen, and the rate equation to meet these findings was derived. The Michaelis–Menten constant determined by using this equation (K_m1 and K_m2) was 23.9 mmol dm^–3 for the substrate and 0.030 mmol dm^–3 for the mediator, suggesting that the electron transfer between isocitrate dehydrogenase and the substrate is the rate-determining step.