KEGG   ENZYME: 4.2.1.122
Entry
EC 4.2.1.122                Enzyme                                 

Name
tryptophan synthase (indole-salvaging);
tryptophan synthase beta2
Class
Lyases;
Carbon-oxygen lyases;
Hydro-lyases
Sysname
L-serine hydro-lyase [adding indole, L-tryptophan-forming]
Reaction(IUBMB)
L-serine + indole = L-tryptophan + H2O [RN:R00674]
Reaction(KEGG)
R00674
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 277:8194-201 (2002)
DOI:10.1074/jbc.M111541200
Other DBs
ExplorEnz - The Enzyme Database: 4.2.1.122
IUBMB Enzyme Nomenclature: 4.2.1.122
ExPASy - ENZYME nomenclature database: 4.2.1.122
BRENDA, the Enzyme Database: 4.2.1.122

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