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Enzyme Commission (EC) Number:
Product Number: E8140


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

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.

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.

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

Synthetic Substrates
Elastin Derived Substrates


Sinha S, Watorek W, Karr S, Giles J, Bode W, Travis J. 1987. Primary structure of human neutrophil elastase.. Proceedings of the National Academy of Sciences. 84(8):2228-2232.
Baugh RJ, Travis J. 1976. Human leukocyte granule elastase: rapid isolation and characterization. Biochemistry. 15(4):836-841.
Barrett AJ. 1981. [44] Leukocyte Elastase.581-588.
Feltelius N, Hallgren R. 1988. Circulating inhibitor bound elastase in patients with ankylosing spondylitis and rheumatoid arthritis and the influence of sulphasalazine treatment.. Annals of the Rheumatic Diseases. 47(1):10-14.
Horwitz M, Benson KF, Duan Z, Person RE, Wechsler J, Williams K, Albani D, Li F. 2003. Role of neutrophil elastase in bone marrow failure syndromes: molecular genetic revival of the chalone hypothesis. Current Opinion in Hematology. 10(1):49-54.
Ceriana P. 1992. Effect of Myocardial Ischaemia-reperfusion on Granulocyte Elastase Release. Anaesthesia and Intensive Care. 20(2):187-190.
Uehara S, Gotoh K, Handa H, Honjo K, Hiraŷama A, Sakamoto W. 1992. Changes in polymorphonuclear neutrophil-elastase in pancreatitis. Agents and actions. Supplements..(38):405-12.
Glinski W, Pierozynska-Dubowska M, Glinska-Ferenz M, Jab?o?ska S. 1991. Decreased specific anti-elastase activity in the uninvolved skin of patients with psoriasis. Arch Dermatol Res. 283(4):224-229.
Kuraki T, Ishibashi M, Takayama M, Shiraishi M, Yoshida M. 2002. A Novel Oral Neutrophil Elastase Inhibitor (ONO-6818) Inhibits Human Neutrophil Elastase-induced Emphysema in Rats. Am J Respir Crit Care Med. 166(4):496-500.
Aasen AO, Ohlsson K. 1978. Release of Granulocyte Elastase in Lethal Canine Endotoxin Shock. 359(1):
Powers JC, Gupton B, Harley A, Nishino N, Whitley RJ. 1977. Specificity of porcine pancreatic elastase, human leukocyte elastase and cathepsin G Inhibition with peptide chloromethyl ketones. Biochimica et Biophysica Acta (BBA) - Enzymology. 485(1):156-166.
IUBMB Enzyme Nomenclature. [Internet]. Available from:
Dubin A, Potempa J, Travis J. 1994. Structural and functional characterization of elastases from horse neutrophils. 300(2):401-406.
Senior RM, Bielefeld DR, Starcher BC. 1976. Comparison of the elastolytic effects of human leukocyte elastase and porcine pancreatic elastase. Biochemical and Biophysical Research Communications. 72(4):1327-1334.
Roughley PJ, Barrett AJ. 1977. The degradation of cartilage proteoglycans by tissue proteinases. Proteoglycan structure and its susceptibility to proteolysis. 167(3):629-637.
Starkey PM, Barrett AJ, Burleigh MC. 1977. The degradation of articular collagen by neutrophil proteinases. Biochimica et Biophysica Acta (BBA) - Enzymology. 483(2):386-397.
Gadek JE, Fells GA, Wright DG, Crystal RG. 1980. Human neutrophil elastase functions as a type III collagen ?Collagenase?. Biochemical and Biophysical Research Communications. 95(4):1815-1822.
Davies M, Barrett AJ, Travis J, Sanders E, Coles GA. 1978. The Degradation of Human Glomerular Basement Membrane with Purified Lysosomal Proteinases: Evidence for the Pathogenic Role of the Polymorphonuclear Leucocyte in Glomerulonephritis. 54(3):233-240.
McDonald J, Kelley D. 1980. Degradation of fibronectin by human leukocyte elastase. Release of biologically active fragments.. Journal of Biological Chemistry. 255(18):8848-58.
Ohlsson K, Odsson I. 1974. The Neutral Proteases of Human Granulocytes. Isolation and Partial Characterization of Granulocyte Elastases. Eur J Biochem. 42(2):519-527.
Liau DF, Yin NX, Ryan SF. 1993. Isolation of Human Polymorphonudear Leukocyte Elastase by Chromatography on Immobilized Benzamidine. Preparative Biochemistry. 23(4):439-447.
Taylor JC, Crawford IP. 1975. Purification and preliminary characterization of human leukocyte elastase. Archives of Biochemistry and Biophysics. 169(1):91-101.