Comparison of substrate and inhibitor specificity of arginase and nitricm oxide (NO) synthase for arginine analogs and related compounds in murine and rat macrophages

A. Hrabåk, T. Bajor, Ågnes Temesi

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Arginine utilizing enzymes in macrophages showed different specificities for various arginine analogues and derivatives as substrates and inhibitors. Isolated arginase was strongly inhibited by L-canavanine(Can) and L-ornithine(Orn) but only slightly by L-homoarginine(Hom) and L-argininamide(ArgNH2). These effects were not or only weakly observed when released urea was measured in long term cell cultures. On the other hand, both L-canavanine and L-argininamide were substrates for arginase in long-term cultures. The known inhibitors or NO synthase were ineffective. The mechanisms of inhibition were different for L-canavanine and L-ornithine, but clear mechanisms could not be identified). NO synthase was studied only in long term cell cultures without purification. Certain N-guanidino (NG)-substituted arginine derivatives caused a marked inhibition while inhibitors of arginase had only slight or no effect. L-homoarginine was also found to be the substrate of NO synthase.The comparison of these effects of arginine analogues and derivatives made possible a computer-aided approximation for the fitting of active centers of these enzymes to their substrates.

Original languageEnglish
Pages (from-to)206-212
Number of pages7
JournalBiochemical and biophysical research communications
Issue number1
Publication statusPublished - Jan 15 1994


ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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