These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: NADPH-cytochrome c reductase from human neutrophil membranes: purification, characterization and localization.
    Author: Nisimoto Y, Otsuka-Murakami H, Iwata S.
    Journal: Biochem J; 1994 Feb 01; 297 ( Pt 3)(Pt 3):585-93. PubMed ID: 8110198.
    Abstract:
    Neutrophil-membrane-associated NADPH-cytochrome c reductase and cytochrome b558 were separately eluted and highly purified by a combination of ion-exchange Sepharose, N-amino-octylagarose, 2',5'-ADP-Sepharose and heparin-Sepharose column chromatographies. The purified cytochrome c reductase with an apparent molecular mass of 68 kDa contained FMN and FAD (FMN/FAD approx. 1). Cytochrome b558 prepared in the presence of phospholipids and FAD showed marked O2-.-producing activity (Vmax., 8.53 mumol of O2-./min per mg of cytochrome; Km for NADPH 58.8 microM) in a cell-free assay system consisting of cytosol, arachidonate and GTP[S]. However, when it was obtained without FAD added to the purification process, it had negligible FAD and little or no O2-.-forming activity in the reconstituted system. The NADPH oxidase activity was not markedly stimulated on incubation of the purified reductase with either flavinated or flavin-depleted cytochrome b558 in the cell-free system, suggesting that the reductase is not likely to be involved in neutrophil O2-. generation. The purified reductase cross-reacted with polyclonal antibodies against both hepatic NADPH-cytochrome P-450 reductase and a synthetic peptide, ILVGPGTGIAPFRSF, which indicates residues 529-543 located in the glycine-rich NADPH-binding domain of the P-450 reductase, but cytochrome b558 did not produce any immunoreactive bands to these antibodies. These antibodies also produced a positive reaction with a 76 kDa protein from dimethyl sulphoxide-induced HL-60-cell microsomes. After solubilization of the microsomal membranes, the 76 kDa protein was readily converted into a partially proteolysed form (68 kDa) even in the presence of antiproteases. In addition, the microsomal fraction shows a CO difference spectrum with a peak at about 454 nm and a trough at 476 nm in the presence of dithionite, indicating the presence of a cytochrome P-450-like haemoprotein.
    [Abstract] [Full Text] [Related] [New Search]