MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:

Enzymes and Genes:

Arabidopsis thaliana col: tryptophan synthase, beta subunitInferred from experiment: TSB1
tryptophan synthaseInferred from experiment: TSBType2
Escherichia coli K-12 substr. MG1655: tryptophan synthase, β subunit dimerInferred from experiment: trpB
Thermococcus kodakarensis: tryptophan synthase β subunit dimerInferred from experiment: trpB
Thermotoga maritima: tryptophan synthase β1 dimerInferred from experiment: trpB1
tryptophan synthase β2 dimerInferred from experiment: trpB2

Sub-reaction of: (1S,2R)-1-C-(indol-3-yl)glycerol 3-phosphate + L-serine → L-tryptophan + D-glyceraldehyde 3-phosphate + H2O

In Pathway: L-tryptophan biosynthesis

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

Mass balance status: Balanced.

Enzyme Commission Primary Name: tryptophan synthase (indole-salvaging)

Enzyme Commission Synonyms: tryptophan synthase β2

Standard Gibbs Free Energy (ΔrG): -15.4869995 kcal/molInferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
Most mesophilic bacteria have a multimeric tryptophan synthase complex ( EC 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 α subunits, is transferred in an internal tunnel to the β 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 α unit to form a complex, salvages the lost indole back to L-tryptophan. It has a much lower Km for indole than the β subunit of EC

Citations: [Hettwer02, Yee96]

Gene-Reaction Schematic

Expand/Contract the Schematic connections:

Gene-Reaction Schematic

Unification Links: KEGG:R00674, Rhea:26434

Relationship Links: BRENDA:EC:, ENZYME:EC:, IUBMB-ExplorEnz:EC:

Revised 09-Apr-2011 by Caspi R, SRI International


Hettwer02: Hettwer S, Sterner R (2002). "A novel tryptophan synthase beta-subunit from the hyperthermophile Thermotoga maritima. Quaternary structure, steady-state kinetics, and putative physiological role." J Biol Chem 277(10);8194-201. PMID: 11756459

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Yee96: Yee MC, Horn V, Yanofsky C (1996). "On the role of helix 0 of the tryptophan synthetase alpha chain of Escherichia coli." J Biol Chem 271(25);14754-63. PMID: 8662916

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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