Read this article to learn about the therapeutic applications of immobilized enzymes and cells.
The therapeutic applications are dealt with here. There are several limitations for the direct use of enzymes for therapeutic purposes.
These include the poor availability of the enzyme at the site of action, sensitivity to natural inhibitors, degradation by endogenous proteases and immunogenicity of certain enzymes. Some of these limitations can be overcome by employing immobilized enzymes for therapeutic applications.
A few examples are listed below:
1. Immobilized streptokinase and urokinase (on Sephadex) can be used for the treatment of thromboses.
2. Some success has been reported in the treatment of inborn errors by employing immobilized enzymes e.g. phenylalanine hydroxylase to treat phenylketonuria, lysosomal α 1, 4-glucosidase to correct type II glycogen storage disease (Pompe’s disease).
Some other important therapeutic applications of immobilized enzymes and cells are briefly described.
Improved Drug Delivery by Using Immobilized Enzymes:
Urea-urease modulated system:
By using immobilized urease enzyme along with the substrate urea, the drug delivery can be enhanced. As urease splits urea, there is an increase in the pH due to the formation of ammonium hydroxide. The drug located in a pH sensitive bio erodible polymer can be effectively released for its action (Fig. 21.19).
Glucose oxidase-glucose modulated system:
For insulin delivery to the human body, a bio erodible polymeric system containing insulin has been developed. The delivery of insulin can be modulated by immobilized glucose oxidase enzyme (Fig. 21.20). As glucose oxidase acts on glucose, gluconic acid is produced which lowers the pH. The low pH in turn, causes the release of insulin from the bio erodible polymeric system.
Immobilization of Artificial Cells:
An artificial cell primarily consists of a spherical semipermeable membrane with comparable dimensions of a living cell. The biological materials such as enzymes enclosed within the artificial cells can be immobilized. The so immobilized compact artificial cells can function as artificial organs. The important artificial organs constructed include artificial kidney, artificial liver, blood detoxifiers and immunosorbents. Their functioning is however, very limited. Multi-enzyme system can be immobilized in the form of artificial cells for the conversion of a substrate to a product, through a series of reactions.