SYMPOSIUM: Immobilized Enzymes in Food Systems

Abstract

S Intrinsic kinetics of an immobilized enzyme can be different from that of soluble enzyme due to changes of the macromolecule caused by immobilization. Also transport of substrate to enzymic sites on the inert support creates a hindrance to overall reaction. Such diffusional effects on immobilized enzyme reactions were analyzed in terms of effectiveness factor and film factor employing the theories developed earlier in heterogeneous catalysis. The pore diffusion effect in the design of an integral reactor was analytically treated. A brief discussion was given to the diffusional effects in relation to common kinetic studies of immobilized enzymes.

Mass Transport Limitations Reduce the Effective Stereospecificity in Enzyme-Catalyzed Kinetic Resolution

“…On the other hand, internal diffusion restrictions are likely to occur in porous particles such as aggregates and immobilized enzymes. A mathematical description of the diffusion limitations for enzymes obeying the Michaelis−Menten kinetics has been established . The extent of mass transfer control can be expressed by the effectiveness factor η, which is the ratio between the observed rate of reaction and the hypothetical rate in the absence of mass transfer.…”

Calcium alginate immobilization of mammalian neurons: A potential tool to purify ligands of neuronal membrane proteins

“…According to Lee and Tsao (1974), the general equation describing the mass balance of a solute substrate S over an alginate gel bead (considered as a spherical porous particle) is as follow if we consider that the substrate consumption proceeds according to Michaelis-Menten kinetics: Dc(82S/Sx 2 + 2/x 8S/8x) -V m (S/(Km+ S)) --0 Diffusional part Reactional part where S is the subst~ate eoncemratiom De the diffusion factor, x the distance inside the bead, K m the affinity constant of cells for substrate and V m the maximal rate of subs~ate utilization.…”

Evaluation of dithiobis(thioformate) and S-methyl dithiocarbonate as reactive groups for the immobilization of biological molecules

“…Studies on immobilized enzymes have had considerable impact as shoun from the vast output of publications in the last ten years. Basic information on enzymes can be found in books uhich discuss immobilized enzymes such as: Reed, 1975;Lihitakpr, 1972;Uhitaker, 1976;Zaborsky, 1973;Dunlap, 1974. Reviews on immobilized enzyme have also appeared : Skinner, 1975;Richardson, 1974;Olson and Richardson, 1974;Stanley and Olson, 1974;Hultin, 1974;Lee and Tsao, 1974;Smiley and Strandberg, 1972;Nelrose, 1971;Gryszkieuicz, 1971;Orth and Brummer, 1972;Suckling, 1977. The various techniques of immobilization have all been developed as means to enhance the thermal, mechanical, and chemical stability of an enzyme so that it becomes a recoverable catalyst.…”