The purification of recombinant human 4-HPPD.

aSteps I to III indicate the pooled fractions after the Q-Sepharose column, after the SOURCE 15PHE column and concentrated fractions pooled after the S-100 Sephacryl column, respectively. The 4-HPPD activity was measured by the formation of HG in µmol/min (U) using the HPLC assay.步骤I至III分别代表经Q琼脂糖凝胶层析柱（Q-Sepharose column）层析后收集的合并组分、经SOURCE 15PHE层析柱（SOURCE 15PHE column）层析后收集的合并组分，以及经S-100葡聚糖凝胶层析柱（S-100 Sephacryl column）层析后收集并浓缩的合并组分。本研究采用高效液相色谱检测法（HPLC assay），通过检测尿黑酸（HG）的生成量来测定4-羟苯基丙酮酸双加氧酶（4-HPPD）的活性，酶活单位为µmol/min（记为U）。