NPP2, or Ectonucleotide pyrophosphatase/phosphodiesterase 2, is a human gene encoded by ENPP2. It may also be known as: Ectonucleotide pyrophosphatase/phosphodiesterase family member 2; E-NPP 2; Autotaxin; Extracellular lysophospholipase D; LysoPLD; ATX; ATX-X; PD-IALPHA; PDNP2. The encoded protein is an enzyme with an amino acid length of 863 and a mass of 99.0 kDa. NPP2 is a member of the Nucleotide pyrophosphatase/phosphodiesterase family. Homologs of this gene exist in other organisms, including: Frog.