EC Number   |
Substrates |
Organism |
Products |
Reversibility |
|---|
   1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
- |
Sphingobium sp. UG30 |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme converts tetrachlorohydroquinone to trichlorohydroquinone and trichlorohydroquinone to dichlorohydroquinone. The enzyme is involved in degradation of pentachlorophenol a widely used wood preservative |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme converts tetrachlorohydroquinone to trichlorohydroquinone and trichlorohydroquinone to dichlorohydroquinone. The enzyme is involved in degradation of pentachlorophenol, a widely used wood preservative |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme is involved in degradation of pentachlorophenol |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme converts tetrachlorohydroquinone to trichlorohydroquinone and trichlorohydroquinone to dichlorohydroquinone |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme converts tetrachlorohydroquinone to trichlorohydroquinone and trichlorohydroquinone to dichlorohydroquinone. In addition to trichlorohydroquinone and dichlorohydroquinone, the enzyme also produces substantial amounts of 2,3,5-trichloro-6-S-glutathionylhydroquinone and an unidentified isomer of dichloro-S-glutathionylhydroquinone. Treatment of the purified enzyme with dithiothreitol or use of freshly prepared crude extracts dramatically decreases the formation of S-glutathionylhydroquinone and the unidentified isomer of dichloro-S-glutathionylhydroquinone. 2,3,5-Trichloro-6-S-glutathionylhydroquinone and an unidentified isomer of dichloro-S-glutathionylhydroquinone are produced by enzyme that has undergone some type of oxidative damage and are therefore not physiologically relevant products. The fact that the oxidative damage can be repaired by DTT suggests that a cysteine or methionine residue may be involved |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme converts tetrachlorohydroquinone to trichlorohydroquinone and trichlorohydroquinone to dichlorohydroquinone. The enzyme binds the glutathione involved in the thioldisulfide exchange reaction very poorly and does not alter its pKa in order to improve its nucleophilicity. Remarkably, single-turnover kinetic studies show that the enzyme catalyzes this step by approximately 10000fold |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme converts tetrachlorohydroquinone to trichlorohydroquinone and trichlorohydroquinone to dichlorohydroquinone. The enzyme uses glutathione but not NADPH, NADH, dithiothreitol, or ascorbic acid as the reducing agent |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme converts tetrachlorohydroquinone to trichlorohydroquinone and trichlorohydroquinone to dichlorohydroquinone. The reaction does not involve nucleophilic aromatic substitution |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
| 1.21.4.5 | 2,3,5,6-tetrachlorohydroquinone + 2 glutathione |
the enzyme converts tetrachlorohydroquinone to trichlorohydroquinone and trichlorohydroquinone to dichlorohydroquinone. The reaction proceeds by a rapid equilibrium random sequential kinetic mechanism. Substrate analogues that lack a second hydroxyl group cannot be turned over to products, although they can bind to the active site. The rate of the reaction is strongly influenced by the number of electron withdrawing substituents on the substrate. These findings are consistent with a mechanism that begins with ketonization of the deprotonated substrate to form 2,3,5,6-tetrachloro-4-hydroxycyclohexa-2,4-dienone, followed by 1,4-elimination of HCl to from trichlorobenzoquinone. Subsequently, trichlorobenzoquinone is attacked by glutathione to form a glutathione conjugate |
Sphingobium chlorophenolicum |
2,3,6-trichlorohydroquinone + Cl- + glutathione disulfide |
- |
? |
