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Information on EC 4.1.99.1 - tryptophanase
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4.1.99.1 tryptophanaseIUBMB Comments
A pyridoxal-phosphate protein, requiring K+. The enzyme cleaves a carbon-carbon bond, releasing indole and an unstable enamine product that tautomerizes to an imine form, which undergoes a hydrolytic deamination to form pyruvate and ammonia. The latter reaction, which can occur spontaneously, can also be catalysed by EC 3.5.99.10, 2-iminobutanoate/2-iminopropanoate deaminase. Also catalyses 2,3-elimination and beta-replacement reactions of some indole-substituted tryptophan analogues of L-cysteine, L-serine and other 3-substituted amino acids.
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Word Map
- 4.1.99.1
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catabolite
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quinonoid
- transposase
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aldimine
- proteus
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phenol-lyase
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beta-elimination
- thermonuclease
- l-trp
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antitermination
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tryptophan-induced
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pyridoxal-p
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rapid-scanning
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rho-dependent
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phillips
- alvei
- analysis
- food industry
- synthesis
- drug development
- medicine
- biotechnology
The expected taxonomic range for this enzyme is: Bacteria, Archaea, Eukaryota
Synonyms
L-tryptophan indole-lyase, L-tryptophanase, TIL, tna2, TnaA, tnaA2, TNase, Tpase, Trpase, tryptophan indole lyase, 
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topREACTION 
REACTION DIAGRAM
COMMENTARY 
ORGANISM
UNIPROT
LITERATURE
L-tryptophan + H2O = indole + pyruvate + NH3
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L-tryptophan + H2O = indole + pyruvate + NH3
in the reverse direction NH4+ interacts with bound pyridoxal 5'-phosphate to form an imine. Pyruvate is the second substrate, indole the third. alpha-Aminoacrylate functions as a common enzyme-bound intermediate in both synthetic and degradative reactions
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L-tryptophan + H2O = indole + pyruvate + NH3
mechanism that requires two catalytic bases
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L-tryptophan + H2O = indole + pyruvate + NH3
quinonoid intermediate formation involving Tyr71 and Cys298, mechanism, active site preorganization, overview
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L-tryptophan + H2O = indole + pyruvate + NH3
an active site base is essential for activity, and alpha-deuterated substrate exhibits modest primary isotope effects on kcat and kcat/Km, suggesting that substrate deprotonation is partially rate-limiting. Pre-steady state kinetics with enzyme TIL show rapid formation of an external aldimine intermediate, followed by deprotonation to give a quinonoid intermediate absorbing at about 500 nm. The mechanism of TIL requires both substrate strain and acid/base catalysis, and substrate strain is probably responsible for the very high substrate specificity of TIL. Acid-base catalysis mechanism of TIL, overview. The indole ring is preorganized into the active conformation before alpha-deprotonation occurs
L-tryptophan + H2O = indole + pyruvate + NH3
an active site base is essential for activity, and alpha-deuterated substrate exhibits modest primary isotope effects on kcat and kcat/Km, suggesting that substrate deprotonation is partially rate-limiting. Pre-steady state kinetics with enzyme TIL show rapid formation of external an aldimine intermediate, followed by deprotonation to give a quinonoid intermediate absorbing at about 500 nm. The mechanism of TIL requires both substrate strain and acid/base catalysis, and substrate strain is probably responsible for the very high substrate specificity of TIL. Acid-base catalysis mechanism of TIL, overview. The indole ring is preorganized into the active conformation before alpha-deprotonation occurs
L-tryptophan + H2O = indole + pyruvate + NH3
catalyses the reaction in which L-tryptophan is degraded to indole, pyruvate and ammonia via alpha,beta-elimination and beta-replacement mechanisms
L-tryptophan + H2O = indole + pyruvate + NH3
proposed mechanism of tryptophan indole-lyase, overview
L-tryptophan + H2O = indole + pyruvate + NH3
reaction via formation of quinonoid intermediate
L-tryptophan + H2O = indole + pyruvate + NH3
reaction mechanism, overview
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