Space-filling model of elastase.
Crystals of porcine elastase.
molecular biology, elastase is an enzyme from the class of that break down proteases (peptidases) proteins. [1 ]
Forms and classification [ edit ]
genes exist for elastase:
chymotrypsin-like elastase family, member 1
elastase 1, pancreatic
chymotrypsin-like elastase family, member 2A
elastase 2A, pancreatic
chymotrypsin-like elastase family, member 2B
elastase 2B, pancreatic
chymotrypsin-like elastase family, member 3A
elastase 3A, pancreatic
chymotrypsin-like elastase family, member 3B
elastase 3B, pancreatic
chymotrypsin C (caldecrin)
bacteria (including ) also produce elastase. In bacteria, elastase is considered a virulence factor. Pseudomonas aeruginosa
Function [ edit ]
Elastase breaks down
elastin, an elastic fibre that, together with collagen, determines the mechanical properties of connective tissue. The neutrophil form breaks down the Outer membrane protein A (OmpA) of and other E. coli Gram-negative bacteria. Elastase also has the important immunological role of breaking down Shigella virulence factors. This is accomplished through the cleavage of peptide bonds in the target proteins. The specific peptide bonds cleaved are those on the carboxyl side of small, hydrophobic amino acids such as glycine, alanine, and valine. For more on how this is accomplished, see serine protease.
The role of human elastase in disease [ edit ]
Elastase is inhibited by the
acute-phase protein α (A1AT), which binds almost irreversibly to the active site of elastase and 1-antitrypsin trypsin. A1AT is normally secreted by the liver cells into the serum. α (A1AD) leads to uninhibited destruction of elastic fibre by elastase; the main result is 1-antitryspin deficiency pulmonary emphysema.
Cyclic hematopoeiesis [ edit ]
rare disease cyclic hematopoeiesis (also called "cyclic neutropenia") is an autosomal dominant genetic disorder characterised by fluctuating neutrophil granulocyte counts over 21-day periods. During neutropenia, patients are at risk for infections. In 1999, this disease was linked to disorders in the ELA-2 / ELANE gene. Other forms of congenital [2 ] neutropenia also appear to be linked to ELA-2 mutations.
Other diseases [ edit ]
Neutrophil elastase is responsible for the blistering in
bullous pemphigoid, a skin condition, in the presence of antibodies.
The role of bacterial elastase in disease [ edit ]
Elastase has been shown to disrupt
tight junctions, cause proteolytic damage to tissue, break down cytokines and alpha proteinase inhibitor, cleave immunoglobulin A and G ( IgA, IgG), and cleave both C3bi, a component of the complement system, and CR1, a receptor on neutrophils for another complement molecule involved in phagocytosis. The cleavage of IgA, IgG, C3bi, and CR1 contributes to a decrease of the ability of neutrophils to kill bacteria by phagocytosis. Together, all these factors contribute to human pathology.
References [ edit ]
^ Bieth JG (2001). "[The elastases]". J. Soc. Biol. (in French) 195 (2): 173–9. PMID 11723830.
^ Horwitz M, Benson KF, Person RE, Aprikyan AG, Dale DC (1999). "Mutations in ELA2, encoding neutrophil elastase, define a 21-day biological clock in cyclic haematopoiesis". Nat. Genet. 23 (4): 433–6. doi: 10.1038/70544. PMID 10581030.
External links [ edit ]