Abstract
ABSTRACT. It was previously shown that inhibitors such as tosylamido-phenylethyl-chloromethylketone (TPCK) inhibit superoxide production by human neutrophils. These studies suggested that a chymotrypsin-like protease inhibited by TPCK was involved in the activation of the neutrophils oxidative system. In this study, we attempted to define the step in cellular activation and/or cell function inhibited by TPCK. TPCK 10−5 M did not inhibit the following early events thought to be involved in the activation of oxidase. 1) f-met-leu-phe-induced activation of phospholipase C assessed by the production of inositoltris-phosphate (IP3), 2) f-met-leu-phe-induced membrane potential changes, 3) f-met-leu-phe-induced increase in free cytosolic calcium, and 4) phorbol-myristate acetate-induced protein phosphorylation in 32P labeled neutrophils. We also showed that TPCK 10−5 M inhibited bactericidal activity of neutrophils on Staphylococcus aureus, whereas it did not inhibit the ingestion rate of endotoxin-coated Oil red O particles. We conclude that 1) TPCK at the concentration of 10−5 M inhibits superoxide production but not ingestion of Oil red O particles and 2) TPCK inhibits superoxide production at a step distal from calcium mobilization and protein phosphorylation. Radiolabeled TPCK may therefore be a useful tool to study, whether a protease is involved in the activation of the oxidative system distal to second messenger generation.
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Suter, S., Lew, P. & Waldvogel, F. Effect of the Synthetic Inhibitor Tosylamino-Phenylethyl-Chloromethylketone on Chemotactic Peptide Receptor Activation and Superoxide Production in Human Neutrophils. Pediatr Res 20, 848–852 (1986). https://doi.org/10.1203/00006450-198609000-00008
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DOI: https://doi.org/10.1203/00006450-198609000-00008