Kinetic studies dealing with immobilized reversible enzyme system. Experimental evidence for shift of apparent equilibrium constant within bienzyme system.

Two chemostat methods for studying the immobilized enzyme kinetics are presented. The methods are applied to glucose-6-phosphate isomerase immobilized within a proteic membrane. The first method is based on the steady state behavior of a Continuously Stirred Tank Reactor (C.S.T.R.) and the second one on a diffusion-reaction process. The apparent equilibrium ratio between glucose 6-phosphate and fructose 6-phosphate is measured for the immobilized enzyme system. No modification is observed with a monoenzyme membrane. In the presence of a glucose-6-phosphate dehydrogenase activity the product of the first reaction is trapped by the second one and due to the local intramembrane concentrations an apparent modification of the equilibrium ratio is observed. The apparent modification is studied with the bienzyme membrane as a function of the concentration of NADP co-substrate of the second enzyme. A "Michaelian" relationship is observed.