Tryptophan synthase
From Wikipedia, the free encyclopedia
Tryptophan synthase or tryptophan synthetase is an enzyme (EC 4.2.1.20) that catalyzes the final two steps in the biosynthesis of tryptophan.[1][2] It is commonly found in Eubacteria,[3] Archaebacteria,[4] Protista,[5] Fungi,[6] and Plantae.[7] However, it is absent from Animalia.[8] It is typically found as an α2β2 tetramer.[9][10] The α subunits catalyze the reversible formation of indole and glyceraldehyde-3-phosphate (G3P) from indole-3-glycerol phosphate (IGP). The β subunits catalyze the irreversible condensation of indole and serine to form tryptophan in a pyridoxal phosphate (PLP) dependent reaction. Each α active site is connected to a β active site by a 25 Ångstrom long hydrophobic channel contained within the enzyme. This facilitates the diffusion of indole formed at α active sites directly to β active sites in a process known as substrate channeling.[11] The active sites of tryptophan synthase are allosterically coupled.[12]
Tryptophan Synthase | |||||||||
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Identifiers | |||||||||
EC no. | 4.2.1.20 | ||||||||
CAS no. | 9014-52-2 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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