Bacteriochlorophylls biosynthetic pathways

Figure 24-23 Outline of the biosynthetic pathways for conversion of protoporphyrin IX into the chlorophylls and bacteriochlorophylls. After Bollivar et al.i17...

The two major pigments of protoplasm, heme and chlorophyll, originate from the same biosynthetic chain. The first product of the chain which is committed to the pathway (Fig. 1) is -aminolevulinic acid. The main branch point is the product protoporphyrin. When iron is inserted into the protoporphyrin ring the metalloporphyrin, iron protoporphyrin or heme, is formed in both plants and animals. When magnesium is inserted into the protoporphyrin ring the metalloporphyrin, Mg protoporphyrin, is formed which is converted in a series of steps to chlorophyll and to bacteriochlorophyll this occurs only in photosynthetic organisms. 

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