aromatic amino acid

Aromatic amino acids, excepting histidine, absorb ultraviolet light above and beyond 250 nm and will fluoresce under these conditions. This characteristic is used in quantitative analysis, notably in determining the concentrations of these amino acids in solution.{{Cite journal |last1=Möller | first1=Matías | last2=Denicola | first2=Ana | name-list-style = vanc |date=2002-05-01|title=Protein tryptophan accessibility studied by fluorescence quenching|journal=Biochemistry and Molecular Biology Education|language=en|volume=30|issue=3|pages=175–178|doi=10.1002/bmb.2002.494030030035| s2cid=42862291 |issn=1539-3429|doi-access=free}}{{cite journal | last = Schmid | first = Franz-Xaver | name-list-style = vanc | date = April 2001 | title = Biological Macromolecules: UV‐visible Spectrophotometry | journal = Encyclopedia of Life Sciences | publisher = John Wiley & Sons Ltd | location = Chichester | doi = 10.1038/npg.els.0003142 | isbn = 0470016175 | url= http://www.life.illinois.edu/biochem/455/Lab%20exercises/2Photometry/spectrophotometry.pdf }} Most proteins absorb at 280 nm due to the presence of tyrosine and tryptophan. Of the aromatic amino acids, tryptophan has the highest extinction coefficient; its absorption maximum occurs at 280 nm. The absorption maximum of tyrosine occurs at 274 nm.{{Cite web|url=https://www.biotek.com/resources/application-notes/peptide-and-amino-acid-quantification-using-uv-fluorescence-in-synergy-ht-multi-mode-microplate-reader/|title=Peptide and Amino Acid Quantification Using UV Fluorescence in Synergy HT Multi-Mode Microplate Reader {{!}} April 18, 2003|website=www.biotek.com|access-date=2020-03-23}}

Aromatic amino acids stabilize folded structures of many proteins.{{Cite journal|last1=Xu|first1=Qingping|last2=Biancalana|first2=Matthew|last3=Grant|first3=Joanna C.|last4=Chiu|first4=Hsiu-Ju|last5=Jaroszewski|first5=Lukasz|last6=Knuth|first6=Mark W.|last7=Lesley|first7=Scott A.|last8=Godzik|first8=Adam|last9=Elsliger|first9=Marc-André|last10=Deacon|first10=Ashley M.|last11=Wilson|first11=Ian A.|date=September 2019|title=Structures of single-layer β-sheet proteins evolved from β-hairpin repeats|journal=Protein Science|volume=28|issue=9|pages=1676–1689|doi=10.1002/pro.3683|issn=1469-896X|pmc=6699103|pmid=31306512}}{{Cite journal|last1=Biancalana|first1=Matthew|last2=Makabe|first2=Koki|last3=Yan|first3=Shude|last4=Koide|first4=Shohei|date=May 2015|title=Aromatic cluster mutations produce focal modulations of β-sheet structure|journal=Protein Science|volume=24|issue=5|pages=841–849|doi=10.1002/pro.2657|issn=1469-896X|pmc=4420532|pmid=25645104}} Aromatic residues are found predominantly sequestered within the cores of globular proteins, although often comprise key portions of protein-protein or protein-ligand interaction interfaces on the protein surface.

Aromatic amino acids often serve as the precursors to important biochemicals.

1. Histidine is the precursor to histamine.
2. Tryptophan is the precursor to 5-hydroxytryptophan and then serotonin, tryptamine, auxin, kynurenines, and melatonin.
3. Tyrosine is the precursor to L-DOPA, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and the thyroid hormone thyroxine. It is also precursor to octopamine and melanin in numerous organisms.{{cite journal | vauthors = Han Q, Phillips RS, Li J | title = Editorial: Aromatic Amino Acid Metabolism | journal = Frontiers in Molecular Biosciences | volume = 6 | pages = 22 | date = 2019-04-10 | pmid = 31024928 | pmc = 6468166 | doi = 10.3389/fmolb.2019.00022 | doi-access = free }}
4. Phenylalanine is the precursor to tyrosine.

In plants, the shikimate pathway first leads to the formation of chorismate, which is the precursor of phenylalanine, tyrosine, and tryptophan. These aromatic amino acids are the precursors of many secondary metabolites, all essential to a plant's biological functions, such as the hormones salicylate and auxin. This pathway contains enzymes that can be regulated by inhibitors, which can cease the production of chorismate, and ultimately the organism's biological functions. Herbicides and antibiotics work by inhibiting these enzymes involved in the biosynthesis of aromatic amino acids, thereby rendering them toxic to plants.{{cite journal | vauthors = Tzin V, Galili G | title = The Biosynthetic Pathways for Shikimate and Aromatic Amino Acids in Arabidopsis thaliana | journal = The Arabidopsis Book | volume = 8 | pages = e0132 | date = 2010-05-17 | pmid = 22303258 | pmc = 3244902 | doi = 10.1199/tab.0132 }} Glyphosate, a type of herbicide, is used to control the accumulation of excess greens. In addition to destroying greens, Glyphosate can easily affect the maintenance of the gut microbiota in host organisms by specifically inhibiting the 5-enolpyruvylshikimate-3-phosphate synthase which prevents the biosynthesis of essential aromatic amino acids. Inhibition of this enzyme results in disorders such as gastrointestinal diseases and metabolic diseases.{{cite journal | vauthors = Nielsen LN, Roager HM, Casas ME, Frandsen HL, Gosewinkel U, Bester K, Licht TR, Hendriksen NB, Bahl MI | display-authors = 6 | title = Glyphosate has limited short-term effects on commensal bacterial community composition in the gut environment due to sufficient aromatic amino acid levels | journal = Environmental Pollution | volume = 233 | pages = 364–376 | date = February 2018 | pmid = 29096310 | doi = 10.1016/j.envpol.2017.10.016 | doi-access = free | url = https://pure.au.dk/ws/files/120071491/1_s2.0_S0269749117328099_main.pdf }}

File:(S)-Norcoclaurine-Higenamine Biosynthesis.tif

Animals obtain aromatic amino acids from their diet, but nearly{{efn|There exist parasitic plants, these plants don't have to synthesize amino acids. Carnivorous plants can get amino acids from digestion, too.}} all plants and some micro-organisms must synthesize their aromatic amino acids through the metabolically costly shikimate pathway in order to make them. Histidine, phenylalanine, tryptophan, are essential amino acids for animals. Since they are not synthesized in the human body, they must be derived from the diet. Tyrosine is semi-essential; therefore, it can be synthesized by the animal, but only from phenylalanine. Phenylketonuria, a genetic disorder that occurs as a result of the inability to breakdown phenylalanine, is due to a lack of the enzyme phenylalanine hydroxylase. A dietary lack of tryptophan can cause stunted skeletal development.{{cite journal | vauthors = Moehn S, Pencharz PB, Ball RO | title = Lessons learned regarding symptoms of tryptophan deficiency and excess from animal requirement studies | journal = The Journal of Nutrition | volume = 142 | issue = 12 | pages = 2231S–2235S | date = December 2012 | pmid = 23077198 | doi = 10.3945/jn.112.159061 | doi-access = free }} Excessive intake of aromatic amino acids far beyond levels obtained through normal protein consumption might lead to hypertension,{{cite journal | vauthors = Teymoori F, Asghari G, Mirmiran P, Azizi F | title = High dietary intake of aromatic amino acids increases risk of hypertension | journal = Journal of the American Society of Hypertension | volume = 12 | issue = 1 | pages = 25–33 | date = January 2018 | pmid = 29208471 | doi = 10.1016/j.jash.2017.11.004 | doi-access = free }} something which could go un-noticed for a long time in healthy individuals. It could be caused by other factors as well such as the use of various herbs and foods like chocolate which inhibit monoamine oxidase enzymes to varying degrees, and also some medications. Aromatic trace amines like tyramine can displace norepinephrine from peripheral monoamine vesicles and in people taking monoamine oxidase inhibitors (MAOIs) this occurs to the extent of being life threatening.{{Citation needed|date=January 2025}} Blue diaper syndrome is an autosomal recessive disease that is caused by poor tryptophan absorption in the body.

• Aromatic L-amino acid decarboxylase
• Expanded genetic code
• Phenylketonuria
• Tyrosine hydroxylase
• Neurotransmitter

{{notelist}} aromatic Amino acids is a acid that essential for protein synthesis in all living cells that contain a aromatic rings in there side chain

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• {{cite journal | vauthors = Maeda H, Dudareva N | title = The shikimate pathway and aromatic amino Acid biosynthesis in plants | journal = Annual Review of Plant Biology | volume = 63 | pages = 73–105 | year = 2012 | pmid = 22554242 | doi = 10.1146/annurev-arplant-042811-105439 }}
• {{cite web | work = Genetics Home Reference | date = 2020 | title = Tyrosine hydroxylase deficiency | publisher = U.S. National Library of Medicine | url = https://ghr.nlm.nih.gov/condition/tyrosine-hydroxylase-deficiency }}

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• {{Commonscatinline|Aromatic amino acids}}
• {{MeshName|Aromatic+Amino+Acids}}

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Category:Amino acids

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