tryptophan synthase activity
Definition
Target type: molecularfunction
Catalysis of the reaction: L-serine + (1S,2R)-1-C-(indol-3-yl)glycerol 3-phosphate = L-tryptophan + glyceraldehyde 3-phosphate + H2O. [RHEA:10532]
Tryptophan synthase activity catalyzes the final step in the biosynthesis of tryptophan, a crucial amino acid. This reaction involves two distinct but coupled enzymatic activities: **alpha-subunit activity** and **beta-subunit activity**.
**Alpha-subunit activity** involves the condensation of indole and serine to form L-O-carboxyphenylamino-D-glyceraldehyde, which is then converted to L-alpha-amino-beta-indolylpropionic acid. This conversion is facilitated by pyridoxal phosphate (PLP), a coenzyme.
**Beta-subunit activity** utilizes L-alpha-amino-beta-indolylpropionic acid, along with a molecule of glyceraldehyde-3-phosphate (GAP), and performs a transamination reaction, generating L-tryptophan and D-glyceraldehyde-3-phosphate. This step also requires PLP.
The coordinated action of both subunits enables the efficient conversion of indole and serine into tryptophan. This complex reaction pathway highlights the intricate mechanism by which enzymes can catalyze multi-step reactions, crucial for cellular function.'
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Proteins (4)
| Protein | Definition | Taxonomy |
|---|---|---|
| Tryptophan synthase beta chain | A tryptophan synthase beta chain that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A879] | Escherichia coli K-12 |
| Tryptophan synthase beta chain | A tryptophan synthase beta chain that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A879] | Escherichia coli K-12 |
| Tryptophan synthase alpha chain | A tryptophan synthase alpha chain that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A877] | Escherichia coli K-12 |
| Tryptophan synthase alpha chain | A tryptophan synthase alpha chain that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A877] | Escherichia coli K-12 |
Compounds (1)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| indolepropanol phosphate | 3-(indol-3-yl)propyl phosphate : An monoalkyl phosphate compound having an O-3-(indol-3-yl)propyl substituent. indolepropanol phosphate: binds specifically to the alpha subunit, but not to the beta subunit of tryptophan synthase | indoles; monoalkyl phosphate |