Adenosine deaminase

Adenosine deaminase (ADA) is an enzyme involved in purine metabolism. It is needed for the breakdown of adenosine from food and for the turnover of nucleic acids in tissues.

Function

ADA is present in all human cells, but it is most active in lymphocytes and monocytes. It catalyzes the deamination of adenosine and 2'-deoxyadenosine to inosine and 2'-deoxyinosine, respectively. This is an important step in the purine metabolism pathway, where the amino group is removed from adenosine.

Clinical significance

Deficiency of ADA leads to adenosine deaminase deficiency, a major cause of severe combined immunodeficiency (SCID). The accumulation of deoxyadenosine interferes with the proliferation and differentiation of immune cells, leading to a severely compromised immune system.

Genetics

The ADA gene is located on the long arm of chromosome 20 (20q13.12). It spans over 32 kilobases and contains 12 exons. Mutations in this gene can lead to ADA deficiency and SCID.

See also

• Purine nucleoside phosphorylase
• Adenosine deaminase deficiency
• Severe combined immunodeficiency

References

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