Huang Jin, Gao Xiaoguang, Su Lingling, Liu Xueqiang, Guo Limin, Zhang Zhentao, Zhao Dandan, Hao Jianxiong
College of Food Science and Biology, Hebei University of Science and Technology, Shijiazhuang, 050000, China.
Institute of Agro-Production Storage and Processing, Xinjiang Academy of Agricultural Sciences, Ürümqi, 830091, China.
Planta. 2023 Mar 22;257(5):85. doi: 10.1007/s00425-023-04118-y.
PPO was purified from Cistanche deserticola, and its enzymatic characteristics were clarified. It was found that microwave treatment was an efficient way to inactivate PPO. Polyphenol oxidase (PPO) from Cistanche deserticola was obtained and purified through an acetone precipitation and anion exchange column, the enzymatic characteristics and inactivation kinetics of PPO were studied. The specific activity of PPO was 73135.15 ± 6625.7 U/mg after purification, the purification multiple was 48.91 ± 4.43 times, and the recovery was 30.96 ± 0.27%. The molecular weight of the PPO component is about 66 kDa by SDS-PAGE analysis. The optimum substrate of PPO was catechol (V = 0.048 U/mL, K = 21.70 mM) and the optimum temperature and pH were 30 °C and 7, respectively. When the temperature is above 50 °C, pH < 3 or pH > 10, the enzyme activity can be significantly inhibited. The first-order kinetic fitting shows that microwave inactivation has lesser k values, larger D values and shorter t. It was found that microwave treatment is considered as an efficient and feasible way to inactive PPO by comparing the Z values and E values of the two thermal treatments.
从肉苁蓉中纯化出多酚氧化酶（PPO），并阐明了其酶学特性。发现微波处理是使PPO失活的有效方法。通过丙酮沉淀和阴离子交换柱获得并纯化了肉苁蓉中的多酚氧化酶（PPO），研究了PPO的酶学特性和失活动力学。纯化后PPO的比活力为73135.15±6625.7 U/mg，纯化倍数为48.91±4.43倍，回收率为30.96±0.27%。通过SDS-PAGE分析，PPO组分的分子量约为66 kDa。PPO的最佳底物是邻苯二酚（V = 0.048 U/mL，K = 21.70 mM），最佳温度和pH分别为30℃和7。当温度高于50℃、pH < 3或pH > 10时，酶活性会受到显著抑制。一级动力学拟合表明，微波失活的k值较小，D值较大，t较短。通过比较两种热处理的Z值和E值，发现微波处理被认为是使PPO失活的一种有效且可行的方法。
