13651
Coproporphyrinogen oxidase ( CPO ) catalyzes the sixth step of the heme biosynthetic pathway .
 ( protein: Coproporphyrinogen oxidase, None) , ( protein: heme, None) , ( protein: CPO, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: Coproporphyrinogen oxidase, None) , ( protein: heme, None) , ( protein: CPO, None) 