PR3 is an alias for the gene, Proteinase 3, in humans. Other names include: Myeloblastin; C-ANCA antigen; Leukocyte proteinase 3; PR-3; Neutrophil proteinase 4; NP-4; Wegener autoantigen; AGP7; Myeloblastin ; serine proteinase, neutrophil; Wegener granulomatosis autoantigen; ACPA; C-ANCA; CANCA; MBN; MBT; NP4. The encoded protein is an enzyme with an amino acid length of 256 and a mass of 27.8 kDa. Other isoforms may exist. PR3 is a member of the Peptidase S1 family, Elastase subfamily. This gene shares homology with other species, including: Mouse, Rat, Frog.