adenosine deaminase

An enzyme that converts adenosine to inosine, a housekeeping step in purine metabolism that prevents toxic buildup of adenosine derivatives inside cells. Its most famous role is in the immune system, where developing lymphocytes are exquisitely sensitive to these toxins; children born without functional enzyme develop severe combined immunodeficiency, one of the bubble-boy diseases. The enzyme also appears in food science contexts: adenosine and related nucleotides contribute to the savory, umami character of meat, fish, and fermented products, and their enzymatic transformation during aging and processing shapes flavor development. Diagnostic laboratories measure its activity in body fluids as a marker for certain infections and inflammatory conditions. From immune defense to flavor chemistry, this single enzyme illustrates how basic metabolism touches both health and the sensory quality of food.