The enzymatic characteristic and inhibitors on isozyme of PPO Agaricus bisporus
The activity of Agaricus bisporus PPO was determined by spectrophotometer at 420 nm using catechol as substrate.The effects of reaction time,temperature,pH value,enzyme concentration,substrate concentration and inhibitors on PPO activity of Agaricus bisporus were studied,furthermore,influence of several kinds of inhibitors on PPO isoenzyme was discussed by polyacrylamide gel electrophoresis.The results showed that the optimum reaction time was 3 min,and temperature was 40 ℃,pH was 6.0,enzyme adding amount was 0.1 mL,substrate concentration was 6 mmol/L.The Michaelis constant and Vmax of PPO were 1.317 mmol/L and 18.484 U/min,respectively.Four kinds of inhibitors had different effects on PPO.Electrophoresis showed that Agaricus bisporus PPO isozymes had four band,different food additives had different effect of inhibition on isozyme band,and the order of PPO as sodium sulfi teVccitric acidEDTA-Na.