超高压处理对毛栓菌多酚氧化酶的影响

 以茶多酚为底物，测定毛栓菌多酚氧化酶（Polyphenol Oxidase，PPO）活性的最适pH值为5.0、最适底物浓度为4 mg/mL，经100、300和500 MPa超高压处理10 min的PPO酶活分别是未处理的93%、87%和86%。圆二色谱和高效液相凝胶渗透色谱分析结果显示，100和300 MPa压力处理PPO的圆二色谱位于190~210 nm的正Cotton效应峰分别产生“褶皱”和“分蘖”；高效液相凝胶渗透色谱中的第一时间出峰组分（即最大分子量组分）的保留时间由6.678 min分别提前至1.514和2.296 min。500 MPa压力处理PPO的圆二色谱和高效液相凝胶渗透色谱与对照相比差异更加显著，其圆二色谱中只有一个正Cotton效应峰；其高效液相凝胶渗透色谱中主要组分的色谱峰面积减小（即280 nm的响应值降低）。不同压力处理的PPO的圆二色谱与高效液相凝胶渗透色谱图的差异程度具有对应关系。

Effect of High Pressure Processing on Polyphenol Oxidase from Trametes Trogii

The activity of polyphenol oxidase(PPO) produced from Trametes Trogii was determined through using tea polyphenols as substrate.The pH value and the substrate concentration of strongest activity of PPO are 5.0 and 4 mg/mL,respectively.The activity of PPO processed by ultrahigh pressure of 100,300 and 500 MPa for 10 min accounted for 93%,87% and 86% of that of untreated one.The CD spectra of PPO processed by 100 and 300 MPa pressure respectively displayed folding shape and tillering shape of Cotton effect peak located in 190-210 nm,while the retention time of the first peak fraction(i.e.,the maximum molecular weight fraction) of the two processed PPO on HPGPC profiles were advanced to 1.514 and 2.296 min,respectively from 6.678 min.Compared with control,CD spectrum and HPGPC of PPO treaded by 500 MPa showed more significant difference with only one positive Cotton effect peaks on CD spectra and reduced peak area of main components on HPGPC profiles(ie,the response value of 280 nm decreased).The disparity of CD and HPGPC of PPO treated by various UHPP showed the corresponding difference in the degree