title: Oxidation of n-formyl methionyl chemotactic peptide by human neutrophils.
abstract: Human neutrophils during phagocytosis oxidized the synthetic chemotactic peptide, n-formyl methionyl-leucyl-phenylalanine (n-FMLP), to its sulfoxide derivative (n-FMsLP). The oxidation of n-FMLP by phagocytosing neutrophils was inhibited by methionine, but not by methionine sulfoxide, leucine, or phenylalanine, confirming that it was the methionine moiety of n-FMLP that was oxidized. The oxidation of n-FMLP was also inhibited by myeloperoxidase inhibitors or catalase, but not by SOD or mannitol, suggesting the involvement of the myeloperoxidase system. Since n-FMsLP does not have chemotactic activity, the oxidation of n-FMLP by phagocytosing neutrophils may be one mechanism by which neutrophils modulate the inflammatory process.
mesh_terms: D002374:Catalase / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008715:Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009239:N-Formylmethionine / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D009195:Peroxidase / Q000494:pharmacology; D010587:Phagocytosis
chemical_list: D010455:Peptides; D009239:N-Formylmethionine; D008715:Methionine; D006861:Hydrogen Peroxide; D002374:Catalase; D009195:Peroxidase