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Mediators of Inflammation
Volume 3 (1994), Issue 2, Pages 117-123

Inactivation of α2-Macroglobulin by Activated Human Polymorphonuclear Leukocytes

1Department of Anesthesiology, Centre Hospitalier Universitaire, B35, Belgium
2Center for the Biochemistry of Oxygen, Institut de Chimie, B6, Belgium
3lnstitut Supérieur d'Education Physique et de Kinésithérapie, B21, Belgium
4lnstitut Provincial d'Enseignement Supérieur Paramédical, Liège, Belgium
5Centre de Transfusion Sanguine, Centre Hospitalier Universitaire, B35, Université de Liège, Sart Tilman, Liège 4000, Belgium

Copyright © 1994 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The proteolytic activity of trypsin releases the dye Remazol Brilliant Blue from its high molecular weight substrate, the skin powder (Hide Powder Azure, Sigma), with an increase in absorbance at 595 nm. Active α2- macroglobulin (80 μg/ml) totally inhibits the proteolytic activity of trypsin (14 μg/ml) by trapping this protease. But after a 20 min incubation of α2-macroglobulin at 37°C with 2 × 106 human polymorphonuclear leukocytes activated by N-formyl-L-methionyl-L-leucyl-L-phenylalanine (10−7 M) and cytochalasin B (10−8 M), 100% of trypsin activity was recovered, indicating a total inactivation of α2-macroglobuHn. Incubation with granulocyte myeloperoxidase also inactivates α2-macroglobulin. Hypochlorous acid, a by-product of myeloperoxidase activity, at a concentration of 10−7 M also inactivates α2-macroglobulin, which indicates that an important cause of α2-macroglobulin inactivation by activated polymorphonuclear leukocytes could be the activity of myeloperoxidase.