Defensin interferes with the activation of neutrophil NADPH oxidase in a cell-free system.
HNP-1 [correction of NHP-1], a member of a family of microbicidal cationic, cystine-rich polypeptides abundant in the azurophilic granules of polymorphonuclear leukocytes (PMN) interfered with detergent-induced cell-free activation of superoxide-producing NADPH oxidase. IC50 of 3 microM has been evaluated for this dose dependent effect of defensin. Preactivated oxidase was not affected by HNP-1. The inhibitory effect could be relieved by raising the concentration of the cytosol or by the addition of a partially purified p47-phox. NADPH oxidase activated in the presence of HNP-1 exhibited an increased affinity for NADPH.
Tal
T
T
Department of Biochemistry, Faculty of Life Sciences, Tel-Aviv University, Israel.
Aviram
I
I
D001770:Blood Bactericidal Activity; D001798:Blood Proteins / Q000302:isolation & purification / Q000494:pharmacology* / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D002474:Cell-Free System; D002852:Chromatography, Ion Exchange; D003574:Cytochrome c Group / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D023082:Defensins; D004789:Enzyme Activation; D006801:Humans; D007700:Kinetics; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000097:blood*; D019255:NADPH Oxidases; D009504:Neutrophils / Q000201:enzymology*; D023084:alpha-Defensins
D001798:Blood Proteins; D003574:Cytochrome c Group; D023082:Defensins; D023084:alpha-Defensins; C406413:human neutrophil peptide 1; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases