Partial purification and characterization of a copper-induced anionic peroxidase of sunflower roots

Hager Jouili (1) , Houda Bouazizi (1) , Michel Rossignol (2) , Gisèle Borderies (3) , Elisabeth Jamet (3) , Ezzeddine El Ferjani (1)

1 Laboratoire de Biologie et Physiologie Cellulaires
2 SCBV - Signalisation cellulaire et biotechnologie végétale
3 SCSV - Surfaces Cellulaires et Signalisation chez les Végétaux

Treatment of 14 day-old sunflower seedlings with a toxic amount of copper (50 µM of CuSO4) during 5 days caused significant increase in peroxidase activity in roots. Qualitative analysis of soluble proteins using native anionic PAGE followed by detection of peroxidase activity guaïacol as electron donor in the presence of H2O2 revealed 5 stimulated peroxidases, named A1, A2, A3, A4, and A5. These peroxidases had differential behavior during the period of treatment. A1, A2, A3 and A4 were stimulated in the first period of stress, but rapidly suppressed at 72 h. A5 showed a progressive stimulation which is even increased at 120 h. A1 was partially purified, identified using liquid chromatography coupled to mass spectrometry (LC-MS/MS), and characterized. Effects of pH and temperature on its activity were determined with guaïacol as electron donor. Optima were obtained at pH 8 and at 40°C. Analysis of substrate specificity showed that A1 was active on coniferyl alcohol but not on IAA. Enzymatic activity was inhibited by high concentration of H2O2.

Keywords: Copper; Mass spectrometry; Peroxidase; Root; Sunflower

Domains: Development Biology

Hager Jouili, Houda Bouazizi, Michel Rossignol, Gisèle Borderies, Elisabeth Jamet, et al.. Partial purification and characterization of a copper-induced anionic peroxidase of sunflower roots. Plant Physiology and Biochemistry, 2008, 46 (8-9), pp.760-7. ⟨10.1016/j.plaphy.2008.04.006⟩. ⟨hal-00315669⟩