title: Strategies for identifying synthetic peptides to act as inhibitors of NADPH oxidases, or "all that you did and did not want to know about Nox inhibitory peptides".
abstract: Phagocytes utilize reactive oxygen species (ROS) to kill pathogenic microorganisms. The source of ROS is an enzymatic complex (the NADPH oxidase), comprising a membrane-associated heterodimer (flavocytochrome b (558)), consisting of subunits Nox2 and p22(phox), and four cytosolic components (p47(phox), p67(phox), p40(phox), and Rac). The primordial ROS (superoxide) is generated by the reduction of molecular oxygen by NADPH via redox centers located on Nox2. This process is activated by the translocation of the cytosolic components to the membrane and their assembly with Nox2. Membrane translocation is preceded by interactions among cytosolic components. A number of proteins structurally and functionally related to Nox2 have been discovered in many cells (the Nox family) and these have pleiotropic functions related to the production of ROS. An intense search is underway to design therapeutic means to modulate Nox-dependent overproduction of ROS, associated with diseases. Among drug candidates, a central position is held by synthetic peptides reflecting domains in oxidase components involved in NADPH oxidase assembly. Peptides, corresponding to domains in Nox2, p22(phox), p47(phox), and Rac, found to be oxidase activation inhibitory in vitro, are reviewed. Usually, peptides are inhibitory only when added preceding assembly of the complex. Although competition with intact components seems most likely, less obvious mechanisms are, sometimes, at work. The use of peptides as inhibitory drugs in vivo requires the development of methods to assure cell penetration, resistance to degradation, and avoidance of toxicity, and modest successes have been achieved. The greatest challenge remains the discovery of peptide inhibitors acting specifically on individual Nox isoforms.
authors.affiliation: The Julius Friedrich Cohnheim Laboratory of Phagocyte Research, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Israel.
authors.forename: Iris
authors.initials: I
authors.lastname: Dahan
authors.forename: Edgar
authors.initials: E
authors.lastname: Pick
mesh_terms: D000818:Animals; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D010586:Phagocytes / Q000201:enzymology / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D010455:Peptides; D017382:Reactive Oxygen Species; D019255:NADPH Oxidases; C086986:CYBA protein, human