Adenosine deaminase

• OMIM: 608 958
• UniProt: P00813

The adenosine deaminase (ADA) is the enzyme that catalyzes the conversion of adenosine to inosine. This reaction is part of the recycling of purine nucleotides in all living things except the plants. Human ADA is present in all tissues, especially in T- lymphocytes, in which they bound to DPP4 is localized in the cell contacts between the epithelium and the lymphocyte and, therefore, plays an important role in the immune response. Mutations in the ADA gene can lead to ADA deficiency and this in a severe congenital disorder of the immune system ( SCID).

Elevated levels can be identified (eg tuberculosis) as a highly sensitive detection method in serous body fluids in infections with mycobacteria.

In addition to the ADA binding to DPP4 stabilizes the A1 adenosine receptor in the plasma membrane. Inhibition of ADA in a model of colitis led to a decline in inflammatory markers.

Hereditary adenosine deaminase deficiency

In this congenital enzyme deficiency, the synthesis of dADP, DGDP, dUDP and dCDP is inhibited. The reason for this is an indirect inhibition of the enzyme ribonucleotide reductase. The adenosine deaminase deaminates adenosine to inosine and deoxyadenosine to deoxyinosine. When an enzyme deficiency leads therefore, inter alia, an accumulation of deoxyadenosine which is increasingly phosphorylated to dATP. Increased concentrations of dATP inhibit ribonucleotide reductase, thus the synthesis of other deoxyribonucleotides is inhibited. As a result, there is a disturbance in DNA synthesis, especially the hindered the proliferation of lymphocytes. Sufferers develop, inter alia, a severe immunodeficiency ( severe combined immunodeficiency, SCID)

Catalyzed reaction

H2O NH4

Adenosine is deaminated inosine arises.