|Tryptophan synthase (indole-salvaging)|
|PDB structures||RCSB PDB PDBe PDBsum|
Tryptophan synthase (indole-salvaging) (EC 18.104.22.168, tryptophan synthase beta2) is an enzyme with systematic name L-serine hydro-lyase (adding indole, L-tryptophan-forming).This enzyme catalyses the following chemical reaction
This enzyme salvages the lost indole to L-tryptophan.
Tryptophan is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a non-polar aromatic amino acid. It is essential in humans, meaning the body cannot synthesize it; it must be obtained from the diet. Tryptophan is also a precursor to the neurotransmitter serotonin, the hormone melatonin and vitamin B3. It is encoded by the codon UGG.
Tryptophan synthase or tryptophan synthetase is an enzyme that catalyses the final two steps in the biosynthesis of tryptophan. It is commonly found in Eubacteria, Archaebacteria, Protista, Fungi, and Plantae. However, it is absent from Animalia. It is typically found as an α2β2 tetramer. The α subunits catalyze the reversible formation of indole and glyceraldehyde-3-phosphate (G3P) from indole-3-glycerol phosphate (IGP). The β subunits catalyze the irreversible condensation of indole and serine to form tryptophan in a pyridoxal phosphate (PLP) dependent reaction. Each α active site is connected to a β active site by a 25 angstrom long hydrophobic channel contained within the enzyme. This facilitates the diffusion of indole formed at α active sites directly to β active sites in a process known as substrate channeling. The active sites of tryptophan synthase are allosterically coupled.
Shikimic acid, more commonly known as its anionic form shikimate, is a cyclohexene, a cyclitol and a cyclohexanecarboxylic acid. It is an important biochemical metabolite in plants and microorganisms. Its name comes from the Japanese flower shikimi, from which it was first isolated in 1885 by Johan Fredrik Eykman. The elucidation of its structure was made nearly 50 years later.
Chorismic acid, more commonly known as its anionic form chorismate, is an important biochemical intermediate in plants and microorganisms. It is a precursor for:
Amino acid synthesis is the set of biochemical processes by which the amino acids are produced. The substrates for these processes are various compounds in the organism's diet or growth media. Not all organisms are able to synthesize all amino acids. For example, humans can only synthesize 11 of the 20 standard amino acids, and in time of accelerated growth, histidine, can be considered an essential amino acid.
Cystathionine-β-synthase, also known as CBS, is an enzyme (EC 22.214.171.124) that in humans is encoded by the CBS gene. It catalyzes the first step of the transsulfuration pathway, from homocysteine to cystathionine:
In enzymology, a tryptophan 2'-dioxygenase is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphoribosylanthranilate isomerase [ PRAI ] is an enzyme that catalyzes the third step of the synthesis of the amino acid tryptophan.
Strictosidine synthase (EC 126.96.36.199) a key enzyme in alkaloid biosynthesis. It catalyses the condensation of tryptamine with secologanin to form strictosidine in a formal Pictet–Spengler reaction:
In enzymology, an indole-3-glycerol-phosphate lyase is an enzyme that catalyzes the chemical reaction
In enzymology, an indole-3-glycerol-phosphate synthase (IGPS) (EC 188.8.131.52) is an enzyme that catalyzes the chemical reaction
In enzymology, a tryptophanase (EC 184.108.40.206) is an enzyme that catalyzes the chemical reaction
In enzymology, an aminodeoxychorismate synthase is an enzyme that catalyzes the chemical reaction
In enzymology, a pyrazolylalanine synthase (EC 220.127.116.11) is an enzyme that catalyzes the chemical reaction
In enzymology, a beta-pyrazolylalanine synthase (EC 18.104.22.168) is an enzyme that catalyzes the chemical reaction
In enzymology, a zeatin 9-aminocarboxyethyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, an indole-3-acetate beta-glucosyltransferase is an enzyme that catalyzes the chemical reaction
Indole is an aromatic heterocyclic organic compound with formula C8H7N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indole is widely distributed in the natural environment and can be produced by a variety of bacteria. As an intercellular signal molecule, indole regulates various aspects of bacterial physiology, including spore formation, plasmid stability, resistance to drugs, biofilm formation, and virulence. The amino acid tryptophan is an indole derivative and the precursor of the neurotransmitter serotonin.
7-dimethylallyltryptophan synthase is an enzyme with systematic name dimethylallyl-diphosphate:L-tryptophan 7-dimethylallyltransferase. This enzyme catalyses the following chemical reaction
Indoxyl sulfate, also known as 3-indoxylsulfate and 3-indoxylsulfuric acid, is a metabolite of dietary L-tryptophan that acts as a cardiotoxin and uremic toxin. High concentrations of indoxyl sulfate in blood plasma are known to be associated with the development and progression of chronic kidney disease and vascular disease in humans. As a uremic toxin, it stimulates glomerular sclerosis and renal interstitial fibrosis.