50] Soluble enzyme-albumin conjugates: New possibilities for enzyme replacement therapy

Abstract

Publisher Summary Enzymes, by virtue of their exquisite specificities, low general toxicity, and ability to function under physiological conditions, might be expected to behave as ideal drugs. The potential use of enzymes as a means of therapy in a range of genetic and metabolic diseases, many of them manifested as specific enzyme deficiencies or defects, has long been anticipated but never properly realized. Except in the treatment of a number of digestive disorders, enzymes have not been widely used as therapeutic agents. Several serious drawbacks have limited the common use of enzymes in medicine: (1) availability of the enzyme in a sufficiently pure and nontoxic form, (2) biodegradation of administered enzyme due to proteolysis and heat inactivation, (3) immunological reactivity of the administered enzyme, usually a foreign protein, often bacterial, and (4) delivery of enzyme to appropriate and specific sites of action-tissues, cells, and often intracellular organelles. The concept of packaging enzymes to protect and/or deliver the enzyme using semipermeable microcapsules or artificial cells, lipid vesicles or liposomes, intact cells, and synthetic or biopolymers is very helpful. All of these solutions both solve and create problems especially as they relate to the carriers' interactions with the reticuloendothelial system (RES), the body's primary defense mechanism against particulate foreign materials.