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

，羟甲基胆素通过尿卟III协同合成酶转化尿卟III，再由尿卟脱羧酶催化粪卟III。

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

然，粪卟Ⅲ被运送回线粒体，并通过粪卟氧化酶转化卟IX。

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

，羟甲基胆色烷转化尿卟III，并分别通过尿卟Ⅲ共合酶与尿卟脱羧酶催化形成粪卟Ⅲ。