Current applications of peroxidase in various areas of biotechnology and clinical biochemistry show
the interest for further screening for peroxidase. Thus, peroxidase activities were screened in higher
plants such as Allium sativum, Ipomoea batatas, Raphanus sativus and Sorghum bicolor grown in a
tropical environment. The enzymes were investigated for their specific activities and best physico-
chemical conditions for activity and stabilities. Optima conditions with respect to pH, temperature and
their heat inactivation were determined by monitoring the hydrogen peroxide-dependant oxidation of
guaiacol. Results revealed that peroxidase specific activities in R. sativus were higher than the other
three plant species. Optimum pHs of all screened peroxidase activities were in the acidic range (pH 4.5
to 6.5). Optimum temperatures were ranging from 30 to 40°C. Peroxidase from R. sativus was the most
thermostable enzyme among the four plants. This suggests that R. sativus is a good source of plant
peroxidase, which could be used for various applications.

Allium sativum Ipomoea batatas Raphanus sativus Sorghum bicolor