40] Medical applications of immobilized proteins, enzymes, and cells

Abstract

This chapter discusses the medical applications of immobilized proteins, enzymes, and cells. Microencapsulated catalase is used for enzyme replacement in acatalasemic mice with congenital deficiency of the enzyme catalase. The chapter discusses the use of liposomes for the microencapsulation of enzymes. Liposomes have the advantage of being biodegradable; however, they appear to enhance immune response to the entrapped protein. Multienzyme systems enclosed within artificial cells are used to convert ammonia or urea into amino acids. The chapter also discusses the use of asparaginase and other enzymes in chemotherapy. The use of these enzymes is associated with problems related to toxicity, immunogenicity, and duration of action. Initial attempts at immobilization involved the successful use of microencapsulated asparaginase to suppress the growth of lymphosarcoma in mice. Because of the importance of cancer treatment, extensive study has been carried out since then by many groups using all available immobilization approaches. The immobilized enzymes are used in detoxification, because many of the detoxifying functions in the body are carried out by enzymatic reactions.