Enzyme deficiency diseases

Since erythrocytes, platelets, and leukocytes have received the greatest attention, the discussion that follows will be limited to these carriers. Fibroblasts [180] and hepatocytes [181] have been specifically used as viable sources to deliver missing enzymes in the management of enzyme-deficiency diseases, whereas islets are useful as a cellular transplant to produce insulin [182,183],... 

Several examples of the binding of enzymes to poly(vinyl alcohol) are in the literature. These could possibly be used to treat enzyme deficiency diseases. In a recent example, trypsin was immobilized on poly(vinyl alcohol) fibers using maleic dialdehyde or bromal. While the reaction was more complete with bromal, the reaction with maleic dialdehyde gave a better support which showed decreasing activity with increasing enzyme content. The activity of the bromal activated system was independant of the enzyme content (52 ). Trypsin and papain were attached to poly(vinyl alcohol) by the reaction sequence shown in Equation 13. In this case, the crosslinked poly(vinyl alcohol) is treated by the 1,3-dioxalone derivative and then converted to either the isothiocyanate or the diazonium salt for coupling with the enzyme. The bound enzymes showed significant, altho reduced, activity in each case (53). 

Well-known examples of enzyme deficiency diseases include ... 

CH 10 METABOLISM OF AMMONIA AND NUCLEIC ACIDS Table 10.5 Changes in the concentration of various intermediates of the urea cycle or their metabolites in plasma or urine in various enzyme deficiency diseases in humans ... 

Therapeutic strategies for enzyme deficiency diseases include dietary modification and potential gene therapy or direct enzyme replacement (Table 3-1). 

As with the mucolipidoses and the enzyme-deficiency diseases (see Chapters), strategies using enzyme replacement therapy are being developed fortreatmentof many of the MPS syndromes. 

Enzyme deficiency diseases. A variety of metabolic diseases are caused by deficiencies or malfunctions of enzymes, due originally to gene mutation. Albinism, for example, may be caused by the absence of tyrosinase, an enzyme essential for the production of cellular pigments. The hereditary lack of phenylalanine hydroxylase results in the disease phenylketonuria (PKU) PKU is usually managed by dietary modifications, but intravenous... 

Probes at Replacement Therapy for Enzyme Deficiency Diseases - Reports on use of immunoglobulin-coated liposomes to introduce enzymes into certain cells iri vitro are promising probes at definitive treatment of deficiency diseases.61, 65 These approaches have potential application to other diseases in which novel methods of packaging must be designed to protect the therapeutic agent from the immune surveillance system and other systems expected to interfere with these and other replacement therapies for which the need is enormous. 

Phenylketonuria. Many enzyme deficiency diseases have been discovered that affect the pathways of amino acid metabolism. These deficiency diseases have helped researchers to elucidate the pathways in humans, in whom experimental manipulation is, at best, unethical. These spontaneous mutations ( experiments of nature), although devastating to patients, have resulted in an understanding of these diseases that now permit treatment of inborn errors of metabolism that were once considered to be untreatable. 

Some disorders of proteoglycan metabolism, e.g. Hurler s syndrome, have been shown to be enzyme-deficiency diseases in which a lysosomal enzyme is missing (page 203). 

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