The Evolution of Metabolism

Nothing in biology makes sense except in the light of evolution. 

In biology, many long held categorisations were finally abandoned because they were no longer productive, meaningful or they lacked an adequate evolutionary underpinning. The model for the evolution of metabolism outlined in this chapter explains why the terms primary metabolism and secondary metabolism should now be consigned to history. 

The legacy of the split of NP research from biochemistry— evolutionary theory was not fully exploited 

Primary metabolites (made by primary metabolism)—the basic set of chemicals needed for life and the type of metabolism that is the focus of all biochemistry textbooks and most biochemistry research. 

Secondary metabolites (made by secondary metabolism)—the chemicals made only by some species or families, chemicals that are clearly not essential for life because most organisms do not make any one of them. These chemicals include what this book has called NPs. 

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Melendes-Hevia E, Waddell TG, Shelton ED Optimization of molecular design in the evolution of metabolism the glycogen molecule. BiochemJ 1993 295 477. 

Baldwin JE, Krebs HA The evolution of metabolic cycles. Nature 1981 291 381. 

JK Bhattacharjee. Evolution of a-aminoadipate pathway for the synthesis of lysine in fungi. In RP Mortlock, ed. The Evolution of Metabolic Function. London CRC Press, 1992, pp 47-80. 

In general, it is very likely that the ability to interact with other cell components has also been an important factor in the evolution of metabolism of living organisms. Thus, PolyP, which possesses a monotonic macromolecular, essentially linear, structure without any special features, could have become a somewhat unsatisfactory compound at a certain stage of cell development. The limited capacity of PolyP for precise and very specific interactions with other cellular metabolites resulted in an inconsistency with its function of coupling exo-and endoenergetic processes. Hence, ATP was selected for the above functions, because it has a much more specific, and therefore more readily recognized, structure. Moreover, ATP was capable of many other functions, which could not be performed by PolyP. 

J.E. Baldwin and H. Krebs. 1981. The evolution of metabolic cycles Nature 291 381-382. (PubMed)... 

The physiologic or morphologic evolution is based on the expression of new structural proteins or new enzymes which are translated in cumulative advantages or disadvantages. But the biochemistry evolution is more complex and we, not only should have in mind the appearance of new enzymes or new activities, but the evolution of metabolic environment . 

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