Amino acids natural products probably related

XI. Natural Products Probably Related to the Aromatic Amino Acids... 

The TVD curves of selected amino acids were determined by Contarini and Wendlandt (121). A comparison of the TVD and DSC peak temperature is shown in Table 11.8. The TVD peak temperatures are somewhat higher than those obtained by DSC. Obviously, the kinetics of the electrodedecomposition produces) reaction are different from those of the decomposition reaction. These electrode reactions probably involve one or more diffusion steps between the electrode surface and the amino acid or amino acid decomposition produces), which would be different from the decomposition kinetics themselves. The leading edge of the TVD curve peaks is reproducible to within +1-2%. However, after the peak maximum temperature is attained, the reproducibility falls to within +20% in some cases. This is related to the electrode-amino acid decomposition products interface, which, due to the nature of the reaction, would not be expected to be reproducible. The trailing edge portion of the curve also consists of several shoulder peaks that may be related to the consecutive and/or concurrent reactions previously described in the DSC curves. These reactions could produce decomposition products that would react with the aluminum metal electrode surface. 

In summary, the early ACAGA producers obviously followed chaotic trial-and-error approaches in inventing new pathways toward very similar biochemical solutions iif probably a common physiological problem. However, they did so by means of a limited number of biochemical tools. Thus, the natural compounds treated in this chapter can he regarded as the results of a directed biochemical evolution. However, the route on which these results were reached obviously was of minor importance and could follow altcrna-rive solutions. The easiest explanation for this phenomenon could be that the need for production of ACAGAs and related compounds predated the invention of their now-existing biosynthetic pathways, as is the case for amino acids and nucleotides. Also, the... 

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