has_part protoporphyrinogen ix
Protoporphyrins are tetrapyrroles containing the following ___MASK87___ chains : Protoporphyrin IX is a biochemical widely used as a carrier molecule for divalent cations . Together with ___MASK77___ ( 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 ___MASK51___ - ions ( Mg 2 +) the main part of the Chlorophylls are formed . Complexed with zinc - ions ( Zn 2 +) it forms Zinc protoporphyrin . Porphyrins are ___MASK86___ ___MASK26___ of heterocyclic macrocycle organic compounds , composed of four modified pyrrole subunits interconnected at their  ___MASK18___ atoms via methine bridges (= CH ). The parent porphyrin is porphin , and substituted porphines are called porphyrins . The porphyrin ring structure is aromatic , with ___MASK86___ total of 26 electrons in the conjugated system . Various analyses indicate that not all atoms of the ring are involved equally in the conjugation or that the molecule ' s overall nature is substantially based on several smaller conjugated systems . One result of the large conjugated system is that porphyrin molecules typically have very intense absorption bands in the visible region and may be deeply colored ; the name " porphyrin " comes from the Greek word  (" porphyra "), meaning " purple ". Protoporphyrinogen IX is ___MASK86___ precursor for protoporphyrin IX . See Porphyrins for the pathway and more information . Protoporphyrin IX , in the ___MASK96___ of porphyrin , is created by the enzyme protoporphyrinogen oxidase .