The C2-like beta-barrel domain mediates the Ca2+-dependent resistance of 5-lipoxygenase activity against inhibition by glutathione peroxidase-1

J Biol Chem. 2003 Oct 31;278(44):42846-53. doi: 10.1074/jbc.M302471200. Epub 2003 Jul 31.


Recently, we reported that in crude enzyme preparations, a monocyte-derived soluble protein (M-DSP) renders 5-lipoxygenase (5-LO) activity Ca2+-dependent. Here we provide evidence that this M-DSP is glutathione peroxidase (GPx)-1. Thus, the inhibitory effect of the M-DSP on 5-LO could be overcome by the GPx-1 inhibitor mercaptosuccinate and by the broad spectrum GPx inhibitor iodoacetate, as well as by addition of 13(S)-hydroperoxy-9Z,11E-octadecadienoic acid (13(S)-HPODE). Also, the chromatographic characteristics and the estimated molecular mass (80-100 kDa) of the M-DSP fit to GPx-1 (87 kDa), and GPx-1, isolated from bovine erythrocytes, mimicked the effects of the M-DSP. Intriguingly, only a trace amount of thiol (10 micro M GSH) was required for reduction of 5-LO activity by GPx-1 or the M-DSP. Moreover, the requirement of Ca2+ allowing 5-LO product synthesis in various leukocytes correlated with the respective GPx-1 activities. Mutation of the Ca2+ binding sites within the C2-like domain of 5-LO resulted in strong reduction of 5-LO activity by M-DSP and GPx-1, also in the presence of Ca2+. In summary, our data suggest that interaction of Ca2+ at the C2-like domain of 5-LO protects the enzyme against the effect of GPx-1. Apparently, in the presence of Ca2+, a low lipid hydroperoxide level is sufficient for 5-LO activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arachidonate 5-Lipoxygenase / chemistry*
  • Arachidonate 5-Lipoxygenase / metabolism
  • Azoles / pharmacology
  • Blotting, Western
  • Calcium / metabolism*
  • Cattle
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Inhibitors / pharmacology
  • Glutathione Peroxidase / metabolism*
  • Humans
  • Isoindoles
  • Leukocytes, Mononuclear / metabolism
  • Linoleic Acids / pharmacology
  • Lipid Peroxides / pharmacology
  • Mutagenesis, Site-Directed
  • Organoselenium Compounds / pharmacology
  • Peroxides / metabolism
  • Protein Structure, Tertiary
  • Recombinant Proteins / metabolism
  • Thiomalates / pharmacology


  • Azoles
  • Enzyme Inhibitors
  • Isoindoles
  • Linoleic Acids
  • Lipid Peroxides
  • Organoselenium Compounds
  • Peroxides
  • Recombinant Proteins
  • Thiomalates
  • 13-hydroperoxy-9,11-octadecadienoic acid
  • ebselen
  • 2-thiomalic acid
  • Glutathione Peroxidase
  • Arachidonate 5-Lipoxygenase
  • Calcium