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Nicolas Guyot, Marie-Louise Zani, Patrick Berger, Sandrine Dallet-Choisy, Thierry Moreau

Proteolytic susceptibility of the serine protease inhibitor trappin-2 (pre-elafin): evidence for tryptase-mediated generation of elafin

Keywords: elafin, proteolytic processing, serine protease inhibitor, trappin-2, tryptase

A number of serine, cysteine, metallo- and acid proteases were evaluated for their ability to proteolytically cleave the serine protease inhibitor trappin-2, also known as pre-elafin, and to release elafin from its precursor. None of the metalloproteases or acid proteases examined cleaved trappin-2, while serine and cysteine proteases preferentially cleaved trappin-2 within its non-inhibitory N-terminal moiety. Cathepsin L, cathepsin K, plasmin, trypsin and tryptase were able to release elafin by cleaving the Lys³⁸-Ala³⁹ peptide bond in trappin-2. However, purified tryptase appeared to be efficient at releasing elafin. Incubation of trappin-2 with purified mast cells first challenged with anti-immunoglobulin E or calcium ionophore A23187 resulted in the rapid generation of elafin. This proteolytic release of elafin from trappin-2 was inhibited in the presence of a tryptase inhibitor, suggesting that this mast cell enzyme was involved in the process. Finally, ex vivo incubation of trappin-2 with sputum from cystic fibrosis patients indicated the production of a proteolytic immunoreactive fragment with the same mass as that of native elafin. This cleavage did not occur when preincubating the sputum with polyclonal antibodies directed against tryptase. Taken together, these findings indicate that tryptase could likely be involved in the maturation of trappin-2 into elafin under physiological conditions.

Biological Chemistry, Walter de Gruyter

Print ISSN: 1431-6730
Volume: 386, 04/2005
Pages: 391 - 399

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