Overview of Enzyme Therapies

Highly coordinated chemical reactions, carried out simultaneously in response to the continuously changing cellular environment, are mediated by several enzymeregulating mechanisms. Enzymes are regulated by covalent (e.g., phosphorylation) and proteolytic modifications, binding to stimulatory and inhibitory proteins, and 

Biotechnology and Biopharmaceuticals, by Rodney J. Y. Ho and Milo Gibaldi ISBN 0-471-20690-3 Copyright 2003 by John Wiley Sons, Inc. 

Adenosine Deaminase for Severe Combined Immnnodeficiency Syndrome 

Severe combined immunodehciency (SCID) is an autosomal recessive syn- 

Infants with SCID have profound immunodehciency and present with frequent episodes of diarrhea, pneumonia, otitis, sepsis, and cutaneous infections. Persistent infections with opportunistic organisms such as Pneumocystis carinii, Epstein-Barr virus, Candida albicans, cytomegalovirus, parainhuenzae 3 virus, respiratory syncitial virus, adenovirus, varicella, and bacille Calmette-Guerin (BCG) lead to death within the hrst or second year of life. ADA dehciency also occurs in adults, but with a much later onset and nhlder, but clinically discernible, immunodehciency [3,5]. 

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