Study on the Enzymological Characteristics of PPO in Jialing 30-a New Polyploid Mulberry(Morus L.) Variety for Leaf-and Fruit-Production

The effects of pH,reaction temperature and substrate(catechol) concentration on the activity of polyphenol oxidase(PPO) in Jialing 30,an artificial tetraploid of mulberry,were determined spectrophotometrically.The results showed that the maximum absorption wavelength of PPO of Jialing 30 was 410 nm,the PPO activity was 0.032 nm/min,and the optimum substrate concentration,pH and temperature for it were 0.4 mol/L,4.0 and 25℃,respectively.With a PPO concentration of 0.2-0.4,the reaction rate became accelerated.The effects of inhibitors on PPO activity appeared in the order of vitamin CNa2SO3EDTAcitric acid.