Enzyme Explorer



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Enzyme Commission (EC) Number:
Product Number: E8140

Synonyms: lysosomal elastase, neutrophil elastase, polymorphonuclear leukocyte elastase, serine elastase, lysosomal elastase, granulocyte elastase.

Physical Properties
Leukocyte elastase is a 29KDa serine endoprotease of the Proteinase S1 Family. It exists as a single 238 amino acid-peptide chain with four disulfide bonds. The human leukocyte enzyme shares approximately 43% sequence homology with porcine pancreatic elastase. It contains two or thee N-linked glycans of variable composition which account for its three major isoforms.1,2,3
Isoelectric point: pI = 8.77 - 9.553

Elastase sequence

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Clinical Implications
Elastase is one of the degradative hydrolases contained in the azurophil granules of phygocytic neutrophils.3

Elevated levels of circulating elastase and/or decreased levels of endogenous inhibitors have been implicated in several inflammatory diseases including arthritis,4 Cyclic neutropenia,5 Myocardial Ischemia,6 Pancreatitis,7 Psoriasis,8 Pulmonary Emphysema,9 and endotoxic shock.10

Several inhibitors of leukocyte elastase, including elafin, and have been proposed for treatment of related diseases.

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Specificity, Kinetics and Activity Determination
Unlike pancreatic elastase the leukocyte enzyme has a preferential cleavage for the carboxyl side of valine, but will also cleave to a lesser extent after alanine.11,12,13 Natural substrates include elastin,14 cartilage proteoglycans,15 collagen types I, II, II and IV16,17,18 and fibronectin.19

pH Optimum for activity: 8.520

Sigma’s Unit Definition: One unit will release one nanomole of p-nitrophenol per second from N-t-BOC-L-alanine p-nitrophenyl ester at pH 6.5 at 37°C

Elastase structure

Method: Continuous Spectrophotometric Rate Determination

In a 3.00 ml reaction mix, the final concentrations are 49 mM sodium phosphate, 0.20 mM N-t-BOC-L-alanine p-nitrophenyl ester, 2% (v/v) acetonitrile, and 1 unit of elastase.

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Storage and Stability Detergents such as 0.05-0.2%Triton® X-100 or 0.1% Brij® 35 are often included in reaction and extraction buffers to insure solubilization and reduce adhesion to glass particularly at low ionic strength.2,21

The enzyme retains activity after exposure to 8 M urea and retains 22% of its activity in the presence of 1% SDS. In SDS and 2-mercaptoethanol the enzyme undergoes autolysis giving rise to several low molecular weight fragments.22

Store lyophilized powder at -20°C
Once reconstituted, store in frozen aliquots at or below -20°C

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Product Product Name Add to Cart
M0398 N-(Methoxysuccinyl)-Ala-Ala-Pro-Val-chloromethyl ketone
A1153 Aprotinin from bovine lung lyophilized powder, 3-8 TIU/mg solid
D0879 Diisopropylfluorophosphate
D7910 3,4-Dichloroisocoumarin
E7888 N-Acetyl-eglin C recombinant, expressed in proprietary host
E7280 Elafin from human >90% (by MS, HPLC and SDS-PAGE)
M6159 α2-Macroglobulin from human plasma lyophilized powder, ≥98% (SDS-PAGE)
P7626 Phenylmethanesulfonyl fluoride ≥98.5% (GC)
G8419 GW311616A ≥97% (HPLC), solid
A6150 α1-Antitrypsin from human plasma salt-free, lyophilized powder
A9024 α1-Antitrypsin from human plasma salt-free, lyophilized powder
D0879 Diisopropylfluorophosphate
D7910 3,4-Dichloroisocoumarin

Synthetic Substrates

Product Product Name Add to Cart
S4760 N-Succinyl-Ala-Ala-Ala-p-nitroanilide
B8397 Boc-D-Phe-Ala-Nle-p-nitroanilide
B2017 Boc-Ala-Pro-Nva p-chlorothiobenzyl ester
M9771 N-Methoxysuccinyl-Ala-Ala-Pro-Val-7-amido-4-methylcoumarin
M4765 N-(Methoxysuccinyl)-Ala-Ala-Pro-Val 4-nitroanilide

Elastin Derived Substrates

Product Product Name Add to Cart
E1500 Elastin-orcein
E0502 Elastin–Congo red

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  1. Sinha, S.,et al., Proc. Nat.l Acad. Sci. U S A., 84, 2228–2232 (1987)
  2. Baugh, RJ and Travis, J., Biochemistry, 15, 836-841(1976)
  4. Barrett, A.J.; Methods Enzymol. 80, 581-588 (1981)
  5. Feltelius, N. and Hallgren, R, Ann. Rheum. Dis., 47, 10-4 (1988)
  6. Horrowitz, M., at al., Curr. Opin. Hematol., 10, 49-54 (2003)
  7. Ceriana ,P., Anaesth, Intensive Care, 20, 187-90 (1992)
  8. Uehara, S. et al., Agents Actions Suppl., 38, 405-12 (1992)
  9. Glinsky, W., et al., Psoriasis Arch. Dermatol. Res., 283, 224-9 (1991)
  10. Kuraki, T., et al., Am. J. Respir. Cri.t Care. Med., 166, 496-500 (2002)
  11. Aasen, A.O., Ohlsson, K.,Hoppe Seylers Z. Physiol. Chem., 359, 683-90 (1978)
  12. Powers, J.C., et al., Biochim. Biophys. Acta, 485, 156 (1977)
  13. IUBMB Enzyme Nomenclature: http://www.chem.qmul.ac.uk/iubmb/enzyme/EC3/4/21/37.html
  14. Dubin, A., et al., Biochem. J., 300, 401-406 (1994)
  15. Senior, R.M., et al., Biochem. Biophys. Res. Commun., 72, 1327 (1976)
  16. Roughley, P.J., and Barret, A.J., Biochem. J., 167, 629 (1977)
  17. Starkey, P.M., et al., Biochim. Biophys. Acta, 483, 629 (1977)
  18. Gadek, J.E., et al., Biochem. Biophys. Res. Commun., 95, 1815 (1980)
  19. Davies, M., et al., Clin. Sci. Mol. Med, 54, 233 (1978)
  20. McDonald, J.A., and Kelly, D.G., J. Biol. Chem., 255, 8848 (1980)
  21. Ohlsson, K.; Olsson, I.; Eur. J. Biochem. 42, 519-527 (1974)
  22. Liau, D.F., at al., Prep. Biochem., 23, 439-447 (1993)
  23. Taylor, J.C. and Crawford, I.P., Arch. Biochem. Biophys., 169, 91-101 (1975)

Triton is a registered trademark of Union Carbide Chemicals and Plastics Co., Inc.
Brij is a registered trademark of ICI Surfactants

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