Anaromatic amino acid is anamino acid that includes anaromatic ring.
Among the 20standard amino acids,histidine,phenylalanine,tryptophan,tyrosine, are classified as aromatic.
Aromatic amino acids, exceptinghistidine, absorbultraviolet light above and beyond 250 nm and willfluoresce under these conditions. This characteristic is used in quantitative analysis, notably in determining the concentrations of these amino acids in solution.[1][2] Most proteinsabsorb at 280 nm due to the presence oftyrosine andtryptophan. Of the aromatic amino acids,tryptophan has the highest extinction coefficient; its absorption maximum occurs at 280 nm. The absorption maximum oftyrosine occurs at 274 nm.[3]
Aromatic amino acids stabilize folded structures of many proteins.[4][5] Aromatic residues are found predominantly sequestered within the cores ofglobular proteins, although often comprise key portions ofprotein-protein or protein-ligand interaction interfaces on the protein surface.
Aromatic amino acids often serve as the precursors to important biochemicals.
In plants, the shikimate pathway first leads to the formation ofchorismate, which is the precursor of phenylalanine, tyrosine, and tryptophan. These aromatic amino acids are the precursors of manysecondary metabolites, all essential to a plant's biological functions, such as the hormonessalicylate andauxin. 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.[7]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 gutmicrobiota in host organisms by specifically inhibiting the5-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.[8]
Animals obtain aromatic amino acids from their diet, but nearly[a] all plants and some micro-organisms must synthesize their aromatic amino acids through the metabolically costlyshikimate 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 enzymephenylalanine hydroxylase. A dietary lack of tryptophan can cause stunted skeletal development.[9] Excessive intake of aromatic amino acids far beyond levels obtained through normal protein consumption might lead tohypertension,[10] 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 inhibitmonoamine oxidase enzymes to varying degrees, and also some medications. Aromatictrace amines like tyramine can displace norepinephrine from peripheral monoaminevesicles and in people takingmonoamine oxidase inhibitors (MAOIs) this occurs to the extent of being life threatening.[citation needed]Blue diaper syndrome is anautosomal recessive disease that is caused by poor tryptophan absorption in the body.
Media related toAromatic amino acids at Wikimedia CommonsMetabolism map | ||
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 Majormetabolic pathways inmetro-style map. Click any text (name of pathway or metabolites) to link to the corresponding article. Single lines: pathways common to most lifeforms. Double lines: pathways not in humans (occurs in e.g. plants, fungi, prokaryotes).  Orange nodes:carbohydrate metabolism. Violet nodes:photosynthesis. Red nodes:cellular respiration. Pink nodes:cell signaling. Blue nodes:amino acid metabolism. Grey nodes:vitamin andcofactor metabolism. Brown nodes:nucleotide andprotein metabolism. Green nodes:lipid metabolism. | ||
