title: Decrease in apparent Km for oxygen after stimulation of respiration of rat polymorphonuclear leukocytes.
abstract: The respiratory burst of polymorphonuclear leukocytes, induced by the addition of chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine) and cytochalasin B was found to consist of two phases. The first phase of very rapid oxygen uptake lasted 1-3 min. and was followed by a second more prolonged phase of lower magnitude. The apparent Km for oxygen of unstimulated cells was 9.6 +/- 0.67 microM, while that of the second phase of stimulation was 3.7 +/- 1.6 microM oxygen. The possibility that lowered oxygen concentrations may regulate polymorphonuclear leukocyte activity in some pathological conditions is discussed.
mesh_terms: D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D003571:Cytochalasin B / Q000494:pharmacology; D007700:Kinetics; D009239:N-Formylmethionine / Q000031:analogs & derivatives / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats
chemical_list: D009842:Oligopeptides; D003571:Cytochalasin B; D009239:N-Formylmethionine; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010100:Oxygen