Tryptophan synthase - Wikipedia

AB - Catalytic quinone cofactors derived from post-translational modification of amino acid residues within the enzyme polypeptide have roles in a variety of biological processes ranging from metabolism in bacteria to inflammation and connective tissue maturation in humans. In recent years, studies of the biosynthesis of one of these cofactors, tryptophan tryptophylquinone (TTQ), have provided examples of novel chemistry that is required for the generation of these protein-derived cofactors. A novel c-type diheme enzyme, MauG, catalyzes a six-electron oxidation that completes TTQ biosynthesis in a 119-kDa protein substrate. The post-translational modification reactions proceed via an unprecedented Fe(V) equivalent catalytic intermediate comprising two hemes; one an Fe(IV){double bond, long}O and the other a six-coordinate Fe(IV) with axial ligands provided by amino acid residues. This high-valent diheme species is an alternative to Compound I, an Fe(IV){double bond, long}O heme with a porphyrin or amino acid cation radical, which is typically the reactive intermediate of heme-dependent oxygenases and peroxidases.

The Tryptophan-Dependent Auxin Biosynthesis ..

an enzyme involved in tryptophan 2 biosynthesis, ..

The Biochemical Mechanism of Auxin Biosynthesis by …

"What we have revealed is a new and unusual mechanism that nature uses to synthesize macrocyclic peptides. There is a lot of novel chemistry to be discovered by interrogating bacterial secondary metabolite biosynthetic pathways," Seyedsayamdost said.

biochemical mechanism of auxin biosynthesis

Schramma, K. R.; Bushin, L. B.; Seyedsayamdost, M. R. "Structure and biosynthesis of a macrocyclic peptide containing an unprecedented lysine-to-tryptophan crosslink." Nature Chemistry, 2015, 7, 431.

Major classes of specialised metabolites derived from shikimate, chorismate, Phe, Tyr and Tryptophan.
T1 - Uncovering novel biochemistry in the mechanism of tryptophan tryptophylquinone cofactor biosynthesis

MetaCyc NAD biosynthesis II (from tryptophan)

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Tetrahydrobiopterin

BH4 is an essential factor that carries electrons for redox reactions.

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Explore the truth about tryptophan side effects

XA is a metabolite in the tryptophan oxidation pathway and its formation from tryptophan is a complicated process with a number of enzymes involved in the biochemical pathway. The overall process leading to the formation of XA includes oxidation of tryptophan to formylkynurenine, hydrolysis of formylkynurenine to kynurenine, hydroxylation of kynurenine to 3-HK, transamination of 3-HK to a side chain keto acid intermediate, and intramolecular cyclization of the intermediate to XA (). The chemical process and enzymes involved in this branch pathway of tryptophan metabolism have been studied extensively in mammals. Because metabolites in the tryptophan oxidation pathway influence the color of the compound eyes in insects, there have been a number of earlier reports discussing tryptophan metabolites in relation to insect compound eye development (; ; ; ; ). However, there have been few studies concerning the enzymes involved in the tryptophan oxidation pathway in insects.

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Amino Acid Derivatives: Catecholamine, …

KMO (EC 1.14.13.9), a flavin-containing enzyme, catalyzes the hydroxylation of kynurenine to 3-HK in the tryptophan oxidation pathway. KMO has a key role in tryptophan catabolism and the synthesis of ommochrome pigments in mosquitoes. Early studies of KMO were concerned primarily with its role in eye pigmentation in some insects, including D. melanogaster (; ; ), Lucilia cuprina () and Musca domestica (). In D. melanogaster, the cinnabar (cn) gene (GenBank accession no. NP_523651) was shown to encode KMO () and in a mutant strain of Bombyx mori, the genetic lesion leading to the white-eye phenotype has been identified (). The gene encoding KMO (GenBank accession no. AAO27576) in the yellow fever mosquito, Ae. aegypti, has been named kynurenine hydroxylase (kh) (), and its mutation results in a white-eye phenotype designated as the khw strain (; ). Recent efforts to genetically manipulate mosquitoes to control mosquito-transmitted diseases have raised considerable interest in the KMO gene, because it can serve as an excellent marker that indicates the successful production of transgenic Ae. aegypti (; ;). Sequence analysis of the wild-type and mutant khw cDNAs revealed a deletion of 162 nucleotides in the mutant Ae. aegypti KMO gene near the 3′-end of the deduced coding region and RT-PCR analysis confirmed the transcription of a truncated mRNA in the mutant strain (). The in-frame deletion of the KMO gene results in a loss of 54 amino acids and disrupts a major alpha-helix, which probably accounts for the loss of its activity. Further evidence has shown that the Ae. aegypti white-eye (khw) mutant strain () can be complemented by a wild-type copy of the D. melanogaster cinnabar gene (), thereby providing genetic evidence that the product encoded by the white-eye gene was KMO. Although the D. melanogaster cinnabar gene complements various white-eye and other mutations in Diptera, it does not function well outside this order (). However, the general application of the eye-color genes as broad-spectrum transformation markers in species of Coleoptera has also been discussed ().