Editing Tryptophan (section)

== Biosynthesis and industrial production ==
As an essential amino acid, tryptophan is not synthesized from simpler substances in humans and other animals, so it needs to be present in the diet in the form of tryptophan-containing proteins. Plants and [[microorganism]]s commonly synthesize tryptophan from [[shikimic acid]] or [[anthranilic acid|anthranilate]]:<ref name="pmid7640526">{{cite journal|vauthors=Radwanski ER, Last RL|date=1995|title=Tryptophan biosynthesis and metabolism: biochemical and molecular genetics|journal=The Plant Cell|volume=7|issue=7|pages=921–34|doi=10.1105/tpc.7.7.921|pmc=160888|pmid=7640526}}</ref> anthranilate condenses with [[phosphoribosylpyrophosphate]] (PRPP), generating [[pyrophosphate]] as a by-product. The ring of the [[ribose]] [[Moiety (chemistry)|moiety]] is opened and subjected to reductive [[decarboxylation]], producing indole-3-glycerol phosphate; this, in turn, is transformed into [[indole]]. In the last step, [[tryptophan synthase]] [[catalysis|catalyzes]] the formation of tryptophan from indole and the amino acid [[serine]].

:[[Image:Tryptophan biosynthesis (en).svg|class=skin-invert-image|900px]]

The industrial production of tryptophan is also [[biosynthesis|biosynthetic]] and is based on the [[Industrial fermentation|fermentation]] of [[serine]] and [[indole]] using either wild-type or [[genetically modified bacterium|genetically modified bacteria]] such as ''[[Bacillus amyloliquefaciens|B. amyloliquefaciens]]'', ''[[Bacillus subtilis|B. subtilis]]'', ''[[Corynebacterium glutamicum|C. glutamicum]]'' or ''[[Escherichia coli|E. coli]]''. These strains carry [[mutation]]s that prevent the reuptake of [[aromatic amino acids]] or multiple/overexpressed [[trp operon]]s. The conversion is catalyzed by the enzyme [[tryptophan synthase]].<ref name="pmid12523387">{{cite book | vauthors = Ikeda M | chapter = Amino acid production processes | volume = 79 | pages = 1–35 | year = 2002 | pmid = 12523387 | doi = 10.1007/3-540-45989-8_1 | isbn = 978-3-540-43383-5 | series = Advances in Biochemical Engineering/Biotechnology | title = Microbial Production of l-Amino Acids }}</ref><ref name="pmid22138494">{{cite journal|vauthors=Becker J, Wittmann C|date=2012|title=Bio-based production of chemicals, materials and fuels -Corynebacterium glutamicum as versatile cell factory|journal=Current Opinion in Biotechnology|volume=23|issue=4|pages=631–40|doi=10.1016/j.copbio.2011.11.012|pmid=22138494}}</ref><ref name="pmid18725290">{{cite journal|vauthors=Conrado RJ, Varner JD, DeLisa MP|date=2008|title=Engineering the spatial organization of metabolic enzymes: mimicking nature's synergy|journal=Current Opinion in Biotechnology|volume=19|issue=5|pages=492–9|doi=10.1016/j.copbio.2008.07.006|pmid=18725290}}</ref>