PEROXIDASE ISOZYMES FROM WHEAT-GERM - PURIFICATION AND PROPERTIES

Several cationic peroxidase isozymes were identified in wheat germ. Three of them were purified to homogeneity. The pure enzymes share many properties: they show near identical spectroscopic properties and they are glycoproteins with very similar M(r) values of ca 35 000. They differed, however, in their catalytic behaviour: two of them, C-1 and C-2, oxidized pyrogallol, ascorbic acid and indole acetic acid with the same requirements, turnover number and optimum pH. The other enzyme, C-3, showed in very case a higher activity. The oxidation of indole acetic acid by C-3 was not influenced by Mn2+ or resorcinol. C-3-catalysed oxidation of ascorbic acid was inhibited by hydroxylamine as has been reported for ascorbate peroxidases.