KEGG   ENZYME: 4.2.1.122Help
Entry
EC 4.2.1.122                Enzyme                                 

Name
tryptophan synthase (indole-salvaging);
tryptophan synthase beta2
Class
Lyases;
Carbon-oxygen lyases;
Hydro-lyases
BRITE hierarchy
Sysname
L-serine hydro-lyase [adding indole, L-tryptophan-forming]
Reaction(IUBMB)
L-serine + indole = L-tryptophan + H2O [RN:R00674]
Reaction(KEGG)
Substrate
L-serine [CPD:C00065];
indole [CPD:C00463]
Product
L-tryptophan [CPD:C00078];
H2O [CPD:C00001]
Comment
Most mesophilic bacteria have a multimeric tryptophan synthase complex (EC 4.2.1.20) that forms L-tryptophan from L-serine and 1-C-(indol-3-yl)glycerol 3-phosphate via an indole intermediate. This intermediate, which is formed by the alpha subunits, is transferred in an internal tunnel to the beta units, which convert it to tryptophan. In thermophilic organisms the high temperature enhances diffusion and causes the loss of indole. This enzyme, which does not combine with the alpha unit to form a complex, salvages the lost indole back to L-tryptophan. It has a much lower Km for indole than the beta subunit of EC 4.2.1.20.
History
EC 4.2.1.122 created 2011
Reference
1  [PMID:11756459]
  Authors
Hettwer S, Sterner R
  Title
A novel tryptophan synthase beta-subunit from the hyperthermophile Thermotoga maritima. Quaternary structure, steady-state kinetics, and putative physiological role.
  Journal
J. Biol. Chem. 277 (2002) 8194-201.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 

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