Guyot Nicolas, Zani Marie-Louise, Berger Patrick, Dallet-Choisy Sandrine, Moreau Thierry
INSERM U618 Protéases et Vectorisation Pulmonaires, and IFR 135 Imagerie Fonctionnelle, Université François Rabelais, 10 Boulevard Tonnellé, BP 3223, F-37032 Tours Cedex, France.
Biol Chem. 2005 Apr;386(4):391-9. doi: 10.1515/BC.2005.047.
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 Lys 38 -Ala 39 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.
对多种丝氨酸蛋白酶、半胱氨酸蛋白酶、金属蛋白酶和酸性蛋白酶进行了评估，以确定它们对丝氨酸蛋白酶抑制剂trappin-2（也称为前弹性蛋白）进行蛋白水解切割并从前体中释放弹性蛋白的能力。所检测的金属蛋白酶和酸性蛋白酶均未切割trappin-2，而丝氨酸蛋白酶和半胱氨酸蛋白酶优先在其非抑制性N端部分切割trappin-2。组织蛋白酶L、组织蛋白酶K、纤溶酶、胰蛋白酶和类胰蛋白酶能够通过切割trappin-2中的Lys 38 -Ala 39肽键来释放弹性蛋白。然而，纯化的类胰蛋白酶似乎在释放弹性蛋白方面效率很高。用抗免疫球蛋白E或钙离子载体A23187预先刺激纯化的肥大细胞后，将trappin-2与之孵育，导致弹性蛋白迅速生成。在存在类胰蛋白酶抑制剂的情况下，trappin-2中弹性蛋白的这种蛋白水解释放受到抑制，这表明这种肥大细胞酶参与了该过程。最后，将trappin-2与囊性纤维化患者的痰液进行体外孵育，结果表明产生了一种蛋白水解免疫反应性片段，其质量与天然弹性蛋白相同。当用针对类胰蛋白酶的多克隆抗体预先孵育痰液时，这种切割不会发生。综上所述，这些发现表明，在生理条件下，类胰蛋白酶可能参与了trappin-2向弹性蛋白的成熟过程。
