INFORMATION TO USERSThis materia! was produced from a microfilm copy of the original document. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the original submitted.The following explanation of techniques is provided to help you understand markings or patterns which may appear on this reproduction.

Data reported here and previously indicate that when dextrin is hydrolyzed in the presence of immobilized glucoamylase, use of a larger average molecular weight substrate leads to lower overall rates of hydrolysis, while the maltose concentration during the bulk of the reaction and the maximum glucose concentration are lower than when the soluble form of the enzyme is employed under the same conditions. Computer simulation of the system demonstrated that all three observations were caused by pore diffusion limitation: the first by slow diffusion of substrate, the second by slow diffusion of intermediates, and the third by slow diffusion of glucose. Follow-up experiments with glucoamylase immobilized to particles of different sizes confirmed this finding, as results with the smallest beads were identical to those with soluble glucoamylase.

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.