Adenosine deaminase that may contribute to the degradation of extracellular adenosine, a signaling molecule that controls a variety of cellular responses. Requires elevated adenosine levels for optimal enzyme activity. Binds to cell surfaces via proteoglycans and may play a role in the regulation of cell proliferation and differentiation, independently of its enzyme activity (By similarity). adenosine + H(+) + H2O = inosine + NH4(+) Binds 1 zinc ion per subunit. Homodimer. Interacts with adenosine receptors. Binds heparin (By similarity). The PRB domain is involved in receptor binding, and may be responsible for the cytokine-like growth factor activity due to it's sharing of several structural properties with chemokines. High-affinity binding to heparin/glycosaminoclycan (GAG) is mediated by a large, highly positively charged surface at the interface of dimer's subunits involving approximately residues 30-45, 389-396, and 422-428. Belongs to the metallo-dependent hydrolases superfamily. Adenosine and AMP deaminases family. ADGF subfamily.