EPR SPECTROSCOPY OF DOG-ROSE POLYPHENOLOXIDASE

Polyphenoloxidase(PPO) of dog-rose fruit was extracted and purified th rough (NH4)(2)SO4 precipitation and dialysis. The optimum conditions f or this purpose, i.e., pH and temperature, were determined with 4-meth ylcatechol optimum pH and temperature and found to be pH 8.5 and 20 de grees C, respectively. The inhibition effect of ascorbic acid was inve stigated and the Iso value was found ta be 1.57 x 10(-4) M. The activi ty of dog-rose PPO was investigated by electron paramagnetic resonance (EPR) at different pH levels and temperatures. The optimum conditions obtained from both spectrophotometry and EPR were compared.