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Characterization of human adenosine deaminase
Ciba Foundation Symposium
|January 1, 1977
Summary
Adenosine deaminase deficiency causes severe combined immunodeficiency. This study characterizes the human enzyme and its role in immune cell activation, revealing its complex forms and interactions.
Area of Science:
- Biochemistry
- Immunology
- Cell Biology
Background:
- Adenosine deaminase (ADA) deficiency is linked to severe combined immunodeficiency (SCID).
- Understanding ADA's function is crucial for SCID pathogenesis.
- The role of ADA in monocyte-macrophage activation requires further characterization.
Purpose of the Study:
- To characterize the normal human adenosine deaminase enzyme.
- To investigate the role of adenosine deaminase in monocyte-macrophage activation.
- To elucidate the relationship between ADA deficiency and SCID.
Main Methods:
- Purification of human adenosine deaminase from erythrocytes using immunoabsorbent chromatography.
- Characterization of enzyme properties including molecular weight and subunit composition.
- Analysis of soluble and particulate enzyme forms and their interconversion.
Main Results:
- Human adenosine deaminase was purified 800,000-fold with 31% recovery.
- The homogeneous enzyme contains carbohydrate with a 42,000 subunit molecular weight.
- Active soluble ADA exists in interconvertible forms (36,000, 114,000, 298,000 Da), requiring a 200,000 Da protein for large form conversion.
Conclusions:
- The study provides a detailed characterization of human adenosine deaminase.
- The complex forms and interconversion of ADA suggest intricate regulatory mechanisms.
- Further research is needed to fully understand ADA's role in immune cell function and SCID.