PPX is an alias for the gene, Protein phosphatase 4 catalytic subunit, in humans. Other names include: Serine/threonine-protein phosphatase 4 catalytic subunit; Protein phosphatase X; PP-X; PP4C; Pp4; protein phosphatase X, catalytic subunit; PPH3; PPP4; protein phosphatase 4, catalytic subunit. The encoded protein is an enzyme with an amino acid length of 307 and a mass of 35.1 kDa. Other isoforms may exist. PPX is a member of the PPP phosphatase family, PP-4 (PP-X) subfamily. This gene shares homology with other species, including: Mouse, Fly, Rat, Zebrafish, Frog.