myeloblastin; leukocyte proteinase 3; PR-3; PR3; azurophil granule protein 7; AGP7; Wegener autoantigen; P29; C-ANCA antigen; neutrophil proteinase 4; NP-4 (PRTN3, MBN)

Function

• polymorphonuclear leukocyte serine protease
• degrades elastin, fibronectin, laminin, vitronectin, & collagen types I, III, & IV (in vitro)
• hydrolysis of proteins, including elastin, by preferential cleavage: -Ala-|-Xaa- > -Val-|-Xaa-

Structure

• belongs to the peptidase S1 family, elastase subfamily
• contains 1 peptidase S1 domain

Expression

• cytokines such as tumor necrosis factor may induce expression of myelobastin on the cell surface of neutrophils

Pathology

• autoantigen of c-ANCA (cytoplasmic anti-neutrophil cytoplasmic antibody)
• in the presence of c-ANCA, neutrophils generate reactive oxygen species
• this would implicate c-ANCA in the pathology of Wegener's granulomatosis rather than simply as a marker of the disease
• causes emphysema when administered by tracheal insufflation to hamsters

Laboratory

• proteinase 3 in serum
• proteinase-3 antibody in serum

More general terms

• serine protease trypsin family
• antigen

Additional terms

• anti-neutrophil cytoplasmic antibody (ANCA)

Database

• UniProt: http://www.uniprot.org/uniprot/P24158.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=5657
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:5657
• OMIM: https://mirror.omim.org/entry/177020