EC Number |
Reaction |
Reference |
---|
4.1.99.2 | L-tyrosine + H2O = phenol + 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 TPL show rapid formation of external aldimine intermediate, followed by deprotonation to give a quinonoid intermediate absorbing at about 500 nm. The mechanism of TPL requires both substrate strain and acid/base catalysis, and substrate strain is probably responsible for the very high substrate specificity of TPL. Acid-base catalysis mechanism of TPL, overview |
747245 |
4.1.99.2 | L-tyrosine + H2O = phenol + pyruvate + NH3 |
mechanism |
33453, 33467, 649731, 650039, 650407, 651062, 651086, 652265, 653702 |
4.1.99.2 | L-tyrosine + H2O = phenol + pyruvate + NH3 |
mechanism appears to require two bases, one of which abstracts the proton from the 2-position of the substrate to form a quinonoid intermediate and the second of which acting in concert with proton transfer from the first group to C-1 of the phenolic ring, abstracts the substrate hydroxyl group to facilitate cyclohexadienone formation and subsequent elimination of phenol |
33441 |
4.1.99.2 | L-tyrosine + H2O = phenol + pyruvate + NH3 |
mechanism of alpha,beta-elimination of L-tyrosine catalyzed by enzyme TPL |
746892 |
4.1.99.2 | L-tyrosine + H2O = phenol + pyruvate + NH3 |
mechanism of alpha,beta-elimination of L-tyrosine catalyzed by enzyme TPL, detailed overview |
746580 |
4.1.99.2 | L-tyrosine + H2O = phenol + pyruvate + NH3 |
NH3 is the first substrate which interacts with bound pyridoxal 5'-phosphate, pyruvate is the second substrate |
33447 |
4.1.99.2 | L-tyrosine + H2O = phenol + pyruvate + NH3 |
reversible cleavage of the Cbeta-Cgamma bond of L-tyrosine in the final stage of the beta-elimination, via intermediates: internal aldimine, external aldimine, quinoid, ketoquinoid, alpha-aminoacrylate, and internal aldimine, stepwise mechanism, overview |
727663 |
4.1.99.2 | L-tyrosine + H2O = phenol + pyruvate + NH3 |
single-base racemization mechanism, proceeds with retention of configuration at C-beta |
33444 |