摘要目的 制备大鼠血红素加氧酶-1（HO-1）变异体并测定该变异体的活力和抑制野生型大鼠HO-1作用，为临床防治新生儿高胆红素血症提供一条新途径。方法 分别构建含剪切的野生型大鼠HO-1cDNA和变异体大鼠HO-1cDNA的质粒pcDNA3HO1和pcDNA3HO1Δ25，转染、收集COS-1细胞并破膜。超速离心获取表达产物（可溶性微粒体成份），最终检测表达产物的活力和变异体的竞争抑制性。 结果 野生型大鼠HO-1在转染的COS-1细胞中高度表达，其活力为13?688-15?600单位/毫克蛋白/小时；而变异体HO-1的活力明显下降，仅为1948-2160单位/毫克蛋白/小时。野生型和变异体大鼠HO-1具有类似的泳动度，且其分子量均为30?kDa。当酶促反应中加入与野生型HO-1等量的变异体HO-1后，胆红素水平下降达50%。 结论 变异体HO-1与野生型HO-1竞争性结合底物血红素，从而降低胆红素的形成。

abstractsObjective To prepare rat heme oxygenase-1 (HO-1) mutants and todetermine the activity and inhibition of this mutated enzyme. Methods pcDNA3HO1 containing truncated native rat HO-1 cDNA and pcDNA3HO1Δ25 carrying mutated rat HO-1 cDNA (His25Ala) were constructed, respectively. COS-1 cells transfected with pcDNA3HO1 and pcDNA3HO1Δ25 were collected and their activities were analyzed. Results Native rat HO-1 was highly expressed in transfected cells and its activity was 13?688-15?600 U/mg protein per hour. However, the enzyme activity of mutated HO-1 declined and the value was 1948-2160 U/mg protein per hour. When an equal amount of mutant was added to the enzyme reaction system, the level of bilirubin decreased by 42%. Conclusion The His25Ala mutant reduced the formation of bilirubin, suggesting that the mutant could competely bind the heme with native enzyme.