Myeloperoxidase-dependent oxidative inactivation of neutrophil neutral proteinases and microbicidal enzymes.
The susceptibility of a number of human neutrophil granule enzymes to oxidative inactivation was investigated. Addition of H2O2 to the cell-free medium from stimulated neutrophils resulted in inactivation of all enzymes tested. This was inhibited by azide and methionine, indicating that inactivation was due to myeloperoxidase-derived oxidants. Lysozyme was more than 50% inactivated by one addition of 100 nmol of H2O2/ml, whereas myeloperoxidase, beta-glucuronidase, gelatinase and collagenase were almost completely inactivated by three additions. Cathepsin G was slightly less susceptible, whereas elastase was extremely resistant to oxidative attack. Myeloperoxidase-dependent enzyme inactivation may be a means whereby the neutrophil can terminate the activity of its granule enzymes and control the release of degradative enzymes into the tissues.
Vissers
M C
MC
Department of Pathology, Clinical School of Medicine, Christchurch Hospital, New Zealand.
Winterbourn
C C
CC
D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D003012:Microbial Collagenase / Q000037:antagonists & inhibitors; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology
D011480:Protease Inhibitors; D006861:Hydrogen Peroxide; D009195:Peroxidase; D006026:Glycoside Hydrolases; D003012:Microbial Collagenase