Amino acid pathways

Oldiges, M., Kunze, M., Degenring, D. et al. (2004) Stimulation, monitoring, and analysis of pathway dynamics by metabolic profiling in the aromatic amino acid pathway. Biotechnology Progress, 20, 1623-1633. 

Conceptually interesting is the synthesis of the oxazole system 94 through a Beckmann rearrangement of a-formyl ketoxime dimethyl acetals 93 which demonstrated the possibility of a non-amino acid pathway in the biosynthesis of marine derived oxazoles <06CC1742>. 

Amino Acid Pathways Absent in Mammals Offer Targets for Safe Herbicides Chorismate Is a Common Precursor of the Aromatic Amino Acid Family... 

Amino Acid Pathways Absent in Mammals Offer Targets for Safe Herbicides... 

In many cases the amino acid pathway branches so that two or more amino acids are formed. Aspartate is the precursor of four other amino acids found in proteins Isoleucine, threonine, methionine, and lysine (see fig. 21.2). The first step in this overall pathway entails the conversion of aspartate to /3-aspartyl-phosphate by aspartokinase. One might imagine that all four of the amino acid end products of this pathway would act together to inhibit this enzyme. However, in E. coli a different solution has been found. In this bacterium there are three aspartokinases which appear to be parts of different multienzyme complexes leading to threonine and leucine for aspartokinase I, methionine for aspartokinase II and lysine for aspartokinase III. As might be expected threonine and isoleucine inhibit aspartokinase I,... 

The chemistry of the subclass Zoantharia also shows significant deviation from the Octocorallia. Of 151 zoantharian metabolites reported, 88 (58%) are derived from the amino acid pathway. Zoanthids (order Zoanthidea) contain a high proportion of amino acid derivatives (46, 75%), the... 

Several other important compounds found in the common aromatic amino acid pathway whose overproduction has been studied are shikimic acid (61) and, to a lesser extent, quinic acid (62) (Scheme 19.41).323 Both 61 and 62 are naturally occurring, highly functionalized carbocyclic rings with asymmetric centers, which can be used as starting material for the synthesis of GS4104 (63), a neuraminidase inhibitor discovered by Gilead Sciences and developed by Roche Pharmaceuticals under the trade name of Tamiflu .324 325 Manipulation of the aromatic amino acid pathway in E. coli has allowed for numerous strains to be assembled that produce both 61 and 62 as well as other intermediates.326 327 As reported by Chandran and co-workers, an E. coli strain has been constructed that synthesized 87 g/L (0.5m) of 61 in 36% (mol/mol) yield with a maximum productivity of 5.2 gL- lr1.328... 

Initially, work on the aromatic amino acid pathway of Escherichia coli was focused on the construction of a strain for the overproduction of natural amino acids (phenylalanine, tryptophan, tyrosine). These efforts have focused on ... 

Investigation of Mutant Strains. Murray (14) suggested that the amino acids valine, leucine and isoleucine were precursors of 2-methoxy-3-isopropyl, 3-isobutyl and 3-secbutyl pyrazines, respectively. The effects of mutations in the branched chain amino acid pathways on the synthesis of these compounds was investigated. 

The mutant which was blocked in the synthesis of branched chain amino acids produced very low levels of methoxy pyrazines. Cultures of this mutant did generate a new N peak and produced a strong butter-like aroma. TVo compounds were identified in these cultures as 2,3,5,6-tetramethy1 pyrazine and diacetyl. The synthesis of tetramethylpyrazine by a Corynebacterium glutamicum that was also metabolically blocked in the branched chain amino acid pathway has previously been reported (24). 

I 14. Parents bring in their 2-week-old child fearful that he has ingested a poison. They had delayed disposing one of the child s diapers, and noted a black discoloration where the urine had collected. Later, they realized that all of the child s diapers would turn black if stored as waste for a day or so. Knowing that phenol groups can complex to form colors, which amino acid pathways are implicated in this phenomenon ... 

Pirot S, Jay TM, Glowinski J, Thierry A-M (1994) Anatomical and electrophysiological evidence for an excitatory amino acid pathway from the thalamic mediodorsal nucleus to the prefrontal cortex in the rat. Eur J Neurosci 6 1225-1234. 

Somogyi P, Minson JB, Morilak D. Llewellyn-Smith I. Mcllhinney JR, Chalmers J (1989) Evidence for an excitatory amino acid pathway in the brain.stem and for its involvement in cardiovascular control. Brain Res 496 401-407. 

Metabolites Derived from the Polyketide and Amino Acid Pathways... 

Metabolites Derived from the Amino Acid Pathway... 

In 1967 it was shown by Young et al. [84] that 2,3-DHBA in K. pneumoniae and E. coli is produced via the shikimic acid pathway (Fig. 1). Evidence showed that the centra) intermediate chorismic acid, leading to the aromatic amino acid pathways, is also the precursor for 2,3-DHBA. The formation of 2,3-DHBA required NAD, and Mg (Fig. 4)... 

---