Protoporphyrin
Protoporphyrins are tetrapyrroles containing the following side chains:
Protoporphyrin IX is a biochemical widely used as a carrier molecule for divalent cations. Together with iron (Fe 2+) the body of the heme- group of hemoglobin, myoglobin and many other heme-containing enzymes like cytochrome c and catalase are formed. Complexed with magnesium-ions (Mg 2+) the main part of the Chlorophylls are formed. Complexed with zinc-ions (Zn 2+) it forms Zinc protoporphyrin.