Identification of two active functional domains of human adenylate kinase 5.

A full length cDNA that partially corresponded to human adenylate kinase 5 (AK5) was identified and shown to encode for two separate domains. The full length protein could be divided in two distinct functional domains, a previously unidentified domain of 338 amino acids and a second domain of 198 amino acids that corresponded to the protein characterized as AK5, now called AK5p2. The first domain, AK5p1, phosphorylated AMP, CMP, dAMP and dCMP with ATP or GTP as phosphate donors similarly to AK5p2. Our data demonstrate that human AK5 has two separate functional domains and that both have enzymatic activity.