NADPH OXIDASE: STRUCTURE AND ACTIVATION MECHANISMS (REVIEW). NOTE I

Rev Med Chir Soc Med Nat Iasi. Jan-Mar 2016;120(1):29-33.

Abstract

NADPH oxidase (nicotinamide adenine dinucleotide phosphate-oxidase), with its generically termed NOX isoforms, is the major source of ROS (reactive oxigen species) in biological systems. ROS are small oxygen-derived molecules with an important role in various biological processes (physiological or pathological). If under physiological conditions some processes are beneficial and necessary for life, under pathophysiological conditions they are noxious, harmful. NADPH oxidases are present in phagocytes and in a wide variety of nonphagocytic cells. The enzyme generates superoxide by transferring electrons from NADPH inside the cell across the membrane and coupling them to molecular oxygen to produce superoxide anion, a reactive free-radical. Structurally, NADPH oxidase is a multicomponent enzyme which includes two integral membrane proteins, glycoprotein gp9 1 Phox and adaptor protein p22(phox), which together form the heterodimeric flavocytochrome b558 that constitutes the core of the enzyme. During the resting state, the multidomain regulatory subunits p40P(phox), p47(phox), p67(Phox) are located in the cytosol organized as a complex. The activation of phagocytic NADPH oxidase occurs through a complex series of protein interactions.

Publication types

  • Review

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Adaptor Proteins, Vesicular Transport / chemistry
  • Cytochrome b Group / chemistry
  • Cytosol / chemistry
  • Humans
  • NADPH Oxidases / chemistry*
  • NADPH Oxidases / metabolism
  • Phosphoproteins / chemistry
  • Reactive Oxygen Species / chemistry*
  • Reactive Oxygen Species / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Adaptor Proteins, Vesicular Transport
  • Cytochrome b Group
  • NOXA1 protein, human
  • Phosphoproteins
  • Reactive Oxygen Species
  • neutrophil cytosol factor 67K
  • cytochrome b558
  • NADPH Oxidases