Phenylalanine, synthesis

D- or L-phenylalanine induces the enzyme phenylalanine aminoaminotransferase, which is required for L-phenylalanine synthesis. 

The use of interm iates as substrates in L-phenylalanine synthesis avoids inhibition by metabolites. Phenylpyruvic add, an intermediate precursor in tfie biosynthesis of L-phenylalanine, can be converted to L-phenylalanine. L-aspartic add is often used as an amino donor. The amino group can only be transfdred from an... 

Hydroxyphenyl- pyruvatedioxygenase Hydroxylate phenylalanine Synthesis of tyrosine... 

Attempts to prevent the 3 -0-phosphorylation by protection of the hydroxyl groups (3 -0-methylneamine 92), 4 -0-methylneamine 93) and 3 -0-methylkana-mycin A (/ 70)) led to inactive compounds. The studies of H. Umezawa et al. indicate that the protection of the 3 -hydroxyl group causes a steric hindrance of the binding of the antibiotic to the bacterial ribosomes. These compounds only marginally inhibit the poly-phenylalanine synthesis in a poly-U-ribosome system. 

The ability of glyphosate to block phenylalanine synthesis, resulting in shikimate accumulation, makes this herbicide a useful tool for examining control of secondary metabolism. 

The terminal stage of the synthesis has had some light cast upon it by the results of enzyme studies. It has been shown that prephenic acid is an intermediate in the path from phenylalanine to tyrosine. Moreover, phenylpyruvic acid also lies along the pathway of phenylalanine synthesis. 

L-Phenylalanine aminotransferases (classified as tyrosine aminotransferase, E.C. 2.6.1.5 which also acts on phenylalanine) are enzymes useful in L-phenylalanine synthesis, as mentioned above, and have been studied in various thermophilic bacteria by Schutten et al. [185]. These workers looked at several Bacillus isolates... 

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