The activity and preliminary characterization of peroxidases in leaves of cultivars of date palm, Phoenix dactylifera L.

Peroxidase activity was determined in leaves of 13 cultivars of date palm, Phoenix dactylifera L. Levels of Peroxidase in the crude extracts were found to differ significantly among the cultivars. The desalted 50-95% ammonium sulphate cuts of the crude peroxidase showed differences in heat inactivation. In studying the effect of assay pH on the activity of peroxidase, 6 of the 13 cultivars examined demonstrated a pH optimum at pH 4.6. Three other pH optima, 4.0, 5.0 and 5.6 were shown for 2, 3 and 2 other cultivars, respectively. Two anodic bands of peroxidase were present in all cultivars, when polyacrylamide gel electrophoresis was carried out and followed by staining the gels with guaiacol as substrate. The two anodic peroxidase bands showed little differences on the oasis of their relative mobility. Both of them were characterized by low electrophoretic mobility. The results are discussed with respect to the possible relationship of the peroxidase activity in the vascular fusariosis (Bayoud disease) of the data palm.