adenosine deaminase
    n 1: an enzyme found in mammals that can catalyze the
         deamination of adenosine into inosine and ammonia; "ADA
         deficiency can lead to one form of severe combined
         immunodeficiency disease"; "the gene encoding ADA was one
         of the earlier human genes to be isolated and cloned for
         study" [syn: adenosine deaminase, ADA]