Tryptophan indole-lyase tryptophanase

D- and L- Serine dehydratases (deaminases) Tryptophan indole-lyase (tryptophanase) Tyrosine phenol-lyase ... 

Fig. 16. Rapid-scanning data for the reactions of 5 mM indole (A) and 5 mM benzimidazole (B) with 17.2 iM tryptophan indole-lyase (tryptophanase) that has been preequilibrated with 0.25mM t-alanine. i-Alanine was premixed in both syringes to prevent unwanted concentration changes. In panel A, scans were collected at 15,92.5,170,247.5, 325,402.5,480,557.5, 635, 712.5, 790,867.5, and 945 ms after flow stopped. Spectrum 0 represents the spectrum of the enzyme-alanine complex before mixing with indole. In panel B, scans were collected at 15, 390, 765, 1140, 1515, 1890, 2265,2640, 3015,3390, 3765, and 4140 ms after mixing. Spectrum 0 represents the enzyme-alanine complex before mixing with benzimidazole. [Taken from Phillips (104) with permission.]...

Tryptophanase (L-tryptophan indole-lyase (deaminating) EC 4.1.99.1) belongs to the family of the pyridoxal 5 -phosphate (PLP)-dependent enzymes. It serves in vivo to degrade L-tryptophan, is induced by L-tryptophan, and found in various bacteria, particularly in enteric species. Tryptophanase catalyzes a,/3-elimination1 and /3-replacement reactions on interaction with L-tryptophan and various other /3-substituted amino acids2 ... 

The approaches that have been described in some detail for tryptophan synthase may be applied to other PLP-dependent enzymes. Tryptophan indole lyase, or tryptophanase, catalyzes the PLP-dependent P-elimination of indole from tryptophan to yield indole, pyruvate, and NH4+ (Equation 4). 

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