Next, coprophyrinogen III is brought back into the mitochondria and converted into protoporphyrinogen IX by coproporphyrinogen oxidase.

，粪卟啉原Ⅲ被运送回线粒体，并过粪卟啉原化酶转化为原卟啉原IX。

Afterwards, hydroxymethylbilane is converted to uroporphyrinogen III and catalyzed to coproporphyrinogen III via uroporphyrinogen III cosynthase and uroporphyrinogen decarboxylase, respectively.

之，羟甲基过尿卟啉原III协同合成酶转化为尿卟啉原III，再由尿卟啉原脱羧酶催化为粪卟啉原III。

Afterwards, hydroxymethylbilane is converted to Uroporphyrinogen III and catalyzed to coproporphrinogen III, via uroporphyrinogen III co-synphase and uroporphyrinogen decarboxylase respectively.

之，羟甲基色烷转化为尿卟啉原III，并分别过尿卟啉原Ⅲ共合酶与尿卟啉原脱羧酶催化形成粪卟啉原Ⅲ。