Protoporphyrin IX:

A. Intermediate in heme synthesis
B. Intermediate in heme degradation
  1. A only
  2. B only
  3. Both A and B
  4. Neither A or B


Iron (II) is added to protoporphyrin IX to form heme. In heme degradation, the heme ring is cleaved, producing biliverdin and other products.

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