芒果（芒果品种马尼拉）中多酚氧化酶的纯化及部分生化特性研究
Purification and partial biochemical characterization of polyphenol oxidase from mango (Mangifera indica cv. Manila).
作者信息
Palma-Orozco Gisela, Marrufo-Hernández Norma A, Sampedro José G, Nájera Hugo
机构信息
Unidad Profesional Interdisciplinaria de Biotecnologı́a, Departamento de Bioingenierı́a, Instituto Politécnico Nacional , Acueducto s/n, Col. La Laguna Ticoman, Delegación Gustavo A. Madero, C.P. 07340, México, D.F., Mexico.
出版信息
J Agric Food Chem. 2014 Oct 8;62(40):9832-40. doi: 10.1021/jf5029784. Epub 2014 Sep 26.
Polyphenol oxidase (PPO) is an enzyme widely distributed in the plant kingdom that has been detected in most fruits and vegetables. PPO was extracted and purified from Manila mango (Mangifera indica), and its biochemical properties were studied. PPO was purified 216-fold by hydrophobic interaction and ion exchange chromatography. PPO was purified to homogeneity, and the estimated PPO molecular weight (MW) by SDS-PAGE was ≈31.5 kDa. However, a MW of 65 kDa was determined by gel filtration, indicating a dimeric structure for the native PPO. The isolated PPO showed the highest affinity to pyrogallol (Km = 2.77 mM) followed by 4-methylcatechol (Km = 3.14 mM) and catechol (Km = 15.14 mM). The optimum pH for activity was 6.0. PPO was stable in the temperature range of 20-70 °C. PPO activity was completely inhibited by tropolone, ascorbic acid, sodium metabisulfite, and kojic acid at 0.1 mM.
多酚氧化酶（PPO）是一种广泛分布于植物界的酶，在大多数水果和蔬菜中都能检测到。从马尼拉芒果（芒果）中提取并纯化了PPO，并对其生化特性进行了研究。通过疏水相互作用和离子交换色谱法将PPO纯化了216倍。PPO被纯化至同质，通过SDS-PAGE估计的PPO分子量（MW）约为31.5 kDa。然而，通过凝胶过滤测定的MW为65 kDa，表明天然PPO具有二聚体结构。分离出的PPO对连苯三酚（Km = 2.77 mM）的亲和力最高，其次是4-甲基邻苯二酚（Km = 3.14 mM）和邻苯二酚（Km = 15.14 mM）。活性的最佳pH值为6.0。PPO在20-70°C的温度范围内稳定。在0.1 mM时，托酚酮、抗坏血酸、焦亚硫酸钠和曲酸可完全抑制PPO活性。
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