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4.2.1.122 |
Description |
Tryptophan synthase (indole-salvaging) |
Catalyzed reaction |
O-phospho-L-serine + indole = L-tryptophan + phosphate
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Cofactor |
Pyridoxal-phosphate. |
Comments |
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. |
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These enzymes also catalyze, with lower efficiency, the classic tryptophan synthase (beta subunit) reaction:
L-serine + indole <=> L-tryptophan + H(2)O |
PDB |
4QYS; |
Organisms |
-Archea |
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Family |
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Links |
Enzyme (activities) 4.2.1.122
BRENDA (activities) 4.2.1.122
KEGG (pathways) 4.2.1.122
PLPMDB (PLP mutants) 4.2.1.122
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References |
Articles on 4.2.1.122 |
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last changed |
2018/01/29 14:31 |
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