NPP4 is an alias for the gene, Ectonucleotide pyrophosphatase/phosphodiesterase 4 (putative), in humans. Other names include: Bis(5'-adenosyl)-triphosphatase ENPP4; Ectonucleotide pyrophosphatase/phosphodiesterase family member 4; E-NPP 4; NPP-4. The encoded protein is an enzyme with an amino acid length of 453 and a mass of 51.6 kDa. Other isoforms may exist. NPP4 is a member of the Nucleotide pyrophosphatase/phosphodiesterase family. This gene shares homology with other species, including: Mouse, Rat, Zebrafish, Frog, Chicken.