Effect of Temperature on Guaiacol Peroxidase of <i>Pyrus communis</i>

Peroxidase (EC 1.11.1.7; donor: hydrogen-peroxide oxidoreductase, POD) is one of the key enzymes controlling plant growth, differentiation and development. The enzyme participates in construction, rigidification and eventual lignification of cell walls, biosynthesis of ethylene from 1-aminocyclopropane-1-carboxylic acid and H 2 O 2 , regulation of auxin level through auxin catabolism, protection of tissue from damage and infection by pathogenic microorganisms, the oxidation of indoleacetic acid. For peroxidase activity in wild pears extract one pH optimum was observed at 6.5 that probably belong to atleast one isoenzyme. Activity of peroxidase in presence of guaiacol and H 2 O 2 was optimum after incubation at 40 °C. Maximum activity of peroxidase is 300% .Activity increased to 240%, 300%, 70% and 10% after 60 minute incubation at 30, 40, 45 and 60 °C for peroxidase. Incubation at high temperature (70 °C) was accompanied with decrease of activity to 10% peroxidase activity.