Editorial: Mini Review From the Molecular Base to the Diagnostic Value of Adenosine Deaminase

Adenosine deaminase (ADA) or adenosine aminohydrolase (EC 3.5.4.4) is an important enzyme in purine metabolism. It is involved in the breakdown of dietary adenosine as well as those produced from the turnover of nucleic acids in tissues. Although several enzymes including 5′-nucleotidase, ADA and adenosine kinase are involved in the metabolism of adenosine, its concentration is mainly regulated by the hydrolytic activity of ADA, which converts adenosine and deoxyadenosine nucleosides in an irreversible manner into inosine and deoxyinosine, respectively. This ubiquitous enzyme has been found in a wide variety of microorganisms, bacteria, plants, invertebrates and vertebrates with a highly conserved amino acid sequence. In addition, it is present in all mammalian cells and its primary function in humans is development, differentiation, and maturation of the lymphoid system.