Occurrence, Structure, and Biological Function

Hemes are the prosthetic groups of different proteins like hemoglobin, myoglobin, cytochromes, catalases, and peroxidases. The central 

Cytochromes c are important proteins for evolution research. The comparison of more than 100 amino acid sequences from cytochromes c from very different organisms has demonstrated that the protein was only modified to a minor extent during evolution so that a genealogical tree of organisms could be established by that comparison (25c). 

Unique is the occurrence of different porphyrin derivatives (36-40) named corallistin a-e (26) after the marine sponge Corallistes sp. which was found near to New Caledonia. The chlorophylls C1-C3 (41-43) (27) of some algae also belong to the porphyrin class though chlorophyll pigments usually have the chlorin type framework. An interesting source 

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