Abstract
Purification of peroxidase POII from date palm cv. Agwa fruits were carried out. The molecular mass of POII was 43 kDa. The broad pH optimum of POII at pH's 6.0-7.0 was detected. The maximum activity of POII was detected at 60°C and the enzyme was thermally stable up to 60°C. POII oxidized phenolic compounds such as guaiacol, o-phenylenediamine, o-dianosidine, p-aminoantipyrine, pyrogallol and ABTS in presence of H
2
O
2
as second substrate. The Km values of POII were found to be 6 mM for H
2
O
2
and 25 mM for guaiacol. The enzyme activity of POII was enhanced by Fe
+3
, Cu
+2
, and Co
+2
. In conclusion, POII oxidized some of phenolic compounds, which caused the browning color in tamer stage of date cv. Agwa.