PHOTOCATALYTIC FIXATION OF CARBON-DIOXIDE IN OXOGLUTARIC ACID USING ISOCITRATE DEHYDROGENASE AND CADMIUM-SULFIDE

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.