Department of Biotechnology, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, India.
Prep Biochem Biotechnol. 2013;43(2):137-51. doi: 10.1080/10826068.2012.711793.
A soluble and thermostable peroxidase enzyme (POD) was extracted from the leaf of Citrus medica. The enzyme was purified 15.10-fold with a total yield of 28.6% by ammonium sulfate precipitation followed by Sephadex G-100 gel filtration chromatography. The purified enzyme came as a single band on native polyacrylamide gel electrophoresis (PAGE) as well as sodium dodecyl sulfate (SDS) PAGE. The molecular mass of the enzyme was about 32 kD as determined by SDS-PAGE. The enzyme was optimally active at pH 6.0 and 50°C temperature. The enzyme was active in wide range of pH (5.0-8.0) and temperature (30-80°C). From the thermal inactivation studies in the range of 60-75°C, the half-life (t(1/2)) values of the enzyme ranged from 8 to 173 min. The inactivation energy (Ea) value of POD was estimated to be 21.7 kcal mol(-1). The Km values for guaiacol and H(2)O(2) were 8 mM and 1.8 mM, respectively. This enzyme was activated by some metals and reagents such as Ca(2+), Cu(2+), Mg(2+), Co(2+), ferulic acid, and indole acetic acid (IAA), while it was inhibited by Fe(2+), Zn(2+), Hg(2+), and Mn(2+), L-cysteine, L-proline, and protocatechuic acid.
从柑橘属植物叶片中提取到一种可溶且热稳定的过氧化物酶（POD）。该酶经硫酸铵沉淀和 Sephadex G-100 凝胶过滤层析纯化，回收率为 28.6%，比活提高了 15.10 倍。纯化后的酶在天然聚丙烯酰胺凝胶电泳（PAGE）和十二烷基硫酸钠（SDS）PAGE 中均显示为单一带。SDS-PAGE 测定该酶的分子量约为 32 kD。该酶在 pH 6.0 和 50°C 时具有最佳活性。酶在较宽的 pH（5.0-8.0）和温度（30-80°C）范围内均有活性。在 60-75°C 的热失活动力学研究中，酶的半衰期（t(1/2)）值范围为 8-173 min。POD 的失活动力学参数 Ea 值估计为 21.7 kcal mol(-1)。该酶对愈创木酚和 H(2)O(2)的 Km 值分别为 8 mM 和 1.8 mM。该酶被一些金属和试剂激活，如 Ca(2+)、Cu(2+)、Mg(2+)、Co(2+)、阿魏酸和吲哚乙酸（IAA），而被 Fe(2+)、Zn(2+)、Hg(2+)和 Mn(2+)、L-半胱氨酸、L-脯氨酸和原儿茶酸抑制。
