Adenosine deaminase that may contribute to the degradation of extracellular adenosine, a signaling molecule that controls a variety of cellular responses. Stimulates cell proliferation. adenosine + H(+) + H2O = inosine + NH4(+) Binds 1 zinc ion per subunit. Expression starts at stage 20 in the somites. At stage 22 is also detected in the cement gland, and at stage 30 is expressed in the somites, pronephros, eye, cement gland, neural tube, and neural floor plate. Morpholino knockdown of the protein results in reduced body size, abnormalities of the body axis, and changes in expression of developmental marker genes. Belongs to the metallo-dependent hydrolases superfamily. Adenosine and AMP deaminases family. ADGF subfamily.