Neutrophil elastase
From Wikipedia, the free encyclopedia
Neutrophil elastase (or leukocyte elastase) is a serine protease in the same family as chymotrypsin and has broad substrate specificity. As with other serine proteases it contains a charge relay system composed of the catalytic triad of histidine, aspartate, and serine residues that are dispersed throughout the primary sequence of the polypeptide but that are brought together in the three dimension conformation of the folded protein. The gene encoding neutrophil elastase, ELA2, consists of five exons. It is one of the two human forms of elastase.
The neutrophil form of elastase (EC 3.4.21.37) is 218 amino acids long, with two asparagine-linked carbohydrate chains (see glycosylation). It is present in azurophil granules in the neutrophil cytoplasm. There appear to be two forms of neutrophil elastase, termed IIa and IIb.
Neutrophil elastase is an important protease enzyme that when expressed aberrantly can cause emphysema or emphysematous changes. This involves breakdown of the lung structure and increased airspaces.
Elastases form a subfamily of serine proteases that hydrolyze many proteins in addition to elastin. Humans have six elastase genes which encode the structurally similar proteins elastase 1, 2, 2A, 2B, 3A, and 3B. Elastase 2 hydrolyzes proteins within specialized neutrophil lysosomes, called azurophil granules, as well as proteins of the extracellular matrix following the protein's release from activated neutrophils. Elastase 2 may play a role in degenerative and inflammatory diseases by its proteolysis of collagen-IV and elastin of the extracellular matrix. This protein degrades the outer membrane protein A (OmpA) of E. coli as well as the virulence factors of such bacteria as Shigella, Salmonella and Yersinia. Mutations in this gene are associated with cyclic neutropenia and severe congenital neutropenia (SCN). This gene is clustered with other serine protease gene family members, azurocidin 1 and proteinase 3 genes, at chromosome 19pter. All 3 genes are expressed coordinately and their protein products are packaged together into azurophil granules during neutrophil differentiation.[1]
Contents |
[edit] See also
[edit] External links
[edit] References
[edit] Further reading
- Dale DC, Liles WC, Garwicz D, Aprikyan AG (2002). "Clinical implications of mutations of neutrophil elastase in congenital and cyclic neutropenia.". J. Pediatr. Hematol. Oncol. 23 (4): 208–10. PMID 11846296.
- Horwitz M, Benson KF, Duan Z, et al. (2003). "Role of neutrophil elastase in bone marrow failure syndromes: molecular genetic revival of the chalone hypothesis.". Curr. Opin. Hematol. 10 (1): 49–54. PMID 12483111.
- Ancliff PJ, Gale RE, Linch DC (2003). "Neutrophil elastase mutations in congenital neutropenia.". Hematology 8 (3): 165–71. doi:. PMID 12745650.
- Horwitz M, Benson KF, Duan Z, et al. (2004). "Hereditary neutropenia: dogs explain human neutrophil elastase mutations.". Trends in molecular medicine 10 (4): 163–70. doi:. PMID 15059607.
 |
This enzyme-related article is a stub. You can help Wikipedia by expanding it. |
|
||||||||||||||||||||
