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Monoclonal antibodies (MoAbs) were raised against cytochrome b558, a membrane-bound component of the NADPH:O2 oxidoreductase in human neutrophils. This cytochrome consists of a low-molecular-weight (low-mol-wt) subunit of 22 to 23 Kd, probably encoded by an autosomal gene, and a high-mol-wt subunit of 75 to 90 Kd, encoded on the X-chromosome. MoAb 449(More)
The superoxide-forming NADPH oxidase of human phagocytes is composed of membrane-bound and cytosolic proteins which, upon cell activation, assemble on the plasma membrane to form the active enzyme. Patients suffering from chronic granulomatous disease (CGD) are defective in one of the following components: p47-phox and p67-phox, residing in the cytosol of(More)
Src homology 3 (SH3) domains have been suggested to play an important role in the assembly of the superoxide-forming nicotinamide adenine dinucleotide phosphate (NADPH) oxidase upon activation of phagocytes, which involves the association of membrane-bound and cytosolic components. We studied the translocation of the cytosolic proteins to the plasma(More)
Activation of the human NADPH oxidase requires the interaction of at least four cytosolic proteins and one membrane-bound heterodimeric protein. Src homology 3 (SH3) domains and their proline-rich counterstructures have been shown to play an important role in protein-protein interactions. Because it was found that the cytosolic oxidase components p67phox,(More)
In the X-linked form of chronic granulomatous disease (X91 degrees CGD), the genetic defect is linked to the CYBB locus on the X chromosome. We studied a family with a genetic defect in this gene, consisting of a G----A substitution at the fifth base of the 5' donor splice site of intron 3. This mutation leads to skipping of exon 3 after transcription of(More)
Ascorbic acid (vitamin C) was found to stimulate the chlorinating activity of human myeloperoxidase (donor:hydrogen peroxide oxidoreductase, EC 1.11.1.7) 3-fold in vitro and to shift the pH optimum of the reaction to higher pH values. These effects are due to the conversion by ascorbic acid of inactive compound II formed during turnover into native enzyme.
The NADPH:O2 oxidoreductase (NADPH oxidase) of human neutrophils is converted from a dormant to an active state upon stimulation of the cells. We have studied the soluble fraction that is required for NADPH oxidase activation in a cell-free system. Human neutrophils were separated in a membrane-containing and a soluble fraction. The soluble fraction was(More)
Phagocytic leukocytes contain an activatable NADPH:O2 oxidoreductase. Components of this enzyme system include cytochrome b558, and three soluble oxidase components (SOC I, SOC II, and SOC III) found in the cytosol of resting cells. Previously, we found that SOC II copurifies with, and is probably identical to, a 47-kDa substrate of protein kinase C. In the(More)
Neutrophil NADPH:O2 oxidoreductase activity, essential in the killing of bacteria by neutrophils, can be elicited in a cell-free system that requires plasma membranes, cytosol and sodium dodecyl sulfate. In addition, GTP or its nonhydrolyzable analog guanosine 5'-3-O-(thio)triphosphate (GTP gamma S) enhances NADPH oxidase activity. We investigated the(More)