猪肉中过氧化物酶活性的TMB法研究

Studies on activity of pork peroxidase using TMB

以3，5，3’，5’-四甲基联苯胺（TMB）为底物对猪肉过氧化物酶（POD）的酶学特性以及猪肉不同部位过氧化物酶活性水平进行了较为系统的研究。并以辣根过氧化物酶（HRP）为标准酶获得了酶活性标准曲线。猪肉过氧化物酶在温度38℃，pH4．80时活性最高。酶浓度与酶反应初始阶段的酶活性有较好的线性关系，氢供体底物TMB的最佳浓度为2．80×10^-4mol／L，浓度过大则会抑制酶的活性，氢受体底物过氧化氢的浓度与酶活性有较好的线性关系和较宽的线性范围（0～4．20×10^-3mol／L）。猪肉不同部位如腰条（指外腰条）、里脊（指内腰条）、后腿、前腿、三层、腱子中POD活性大小不同，前三者的POD活性相近且活性较小，而后三者活性较为相近且活性较大。通过辣根过氧化物酶标准曲线可以求估待测样品中POD的活性值。

The pork peroxidase （POD） and its activity in different parts of pork using 3, 5, 3＇, 5＇-tetramethylbenzidine （TMB） were detected and studied. The POD activity was evaluated using horseradish peroxidase （HRP） as a standard enzyme. The pork POD kept its best activity at the temperature of 38 ℃ and pH of 4.80, respectively. The concentration of POD was linear with the POD activity at the initial stages of enzyme reaction. The optimal concentration of TMB for POD activity measurement was 2.80 × 10^-4 mol/L, and the activity would be inhibited if the concentration of TMB was over the value. The concentration of H2O2 was also linear with the POD activity and the linear range was 0 ～ 4.20 × 10^-3 mol/L. The POD activities of the pork in the part of outer-tenderloin, inner-tenderloin and hind leg nearly kept the same and lower than those of the part of foreleg, streaky pork and tendon. The activity value of sample could be estimated according to the standard curve of HRP.