Oxidative Modification of Enzymes by Stimulated Neutrophils
We have previously demonstrated that a variety of enzymic and non-enzymic mixed-function oxidation (MFO) systems catalyze the oxidative inactivation of E. coli glutamine synthetase (GS) and other key metabolic enzymes.1,2 Considerable evidence has been presented that the inactivation of GS correlates with the loss of a single histidine residue and is accompanied by the generation of a protein carbonyl derivative.3 Further oxidation renders the enzyme highly susceptible to known proteases4 as well as to a new class of nonlysomal proteases which exhibit selectivity for the oxidatively modified enzyme.5 These in vitro studies have suggested that oxidative inactivation of enzymes is a marking step for selective degradation of enzymes and is under metabolic control. We have subsequently undertaken studies to examine the possible physiological role of this process in biological systems, and one such system is activation of polymorphonuclear leukocytes (PMN, neutrophils).
KeywordsGlutamine Synthetase Phorbol Myristate Acetate Chronic Granulomatous Disease Glutamine Synthetase Activity Oxidative Inactivation
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