Catechol 1,2-dioxygenases

Spence EL, M Kawamukai, J Sanvoisin, H Braven, TDH Bugg (1996) Catechol dioxygenases from Escherichi coli (MhpB) and Alcaligenes eutrophus (MPCI) sequence analysis and biochemical properties of a third family of extradiol dioxygenases. J Bacteriol 178 5249-5256. 

Wolgel SA, JE Dege, PE Perkins-Olson, CH Juarez-Garcia, RL Crawford, E Mtinck, JD Lipscomb (1993) Purification and characterization of protocatechuate 2,3-dioxygenase from Bacillus macerans a new extradiol catecholic dioxygenase. J Bacterial 175 4414-4426. 

An enzymatic pathway for indole degradation was found in A. niger, inducible by the substrate within a 5-h period during growth. Among the enzymes found, anthranilate hydroxylase, N-formylanthranilate deformylase, 2,3-dihydroxybenzoate decarboxylase, and catechol dioxygenase were isolated, and their activities were demonstrated in a cell-free system [342],... 

Bugg, T. D. H., and Lin, G., Solving the Riddle of the Intradiol and Extradiol Catechol Dioxygenases How Do Enzymes Control Hydroperoxide Rearrangements. J. Chem.Soc. Chem. Commun., 2001. pp. 941-952. 

Figure 13.21 Mononuclear non-haem iron enzymes from each of the five families in structures which are poised for attack by 02. (a) The extradiol-cleaving catechol dioxygenase, 2,3-dihydroxy-biphenyl 1,2-dioxygenase (b) the Rieske dioxygenase, naphthalene 1,2-dioxygenase (c) isopenicillin N-synthase (d) the ot-ketoglutarate dependent enzyme clavaminate synthase and (e) the pterin-dependent phenylalanine hydroxylase. (From Koehntop et al., 2005. With kind permission of Springer Science and Business Media.)...

Other non-heme enzymes that use dioxygen are 4-methoxy-benzoate O-demethylase, extradiol catechol dioxygenases, the oxidoreductase isopenicillin N synthase, and a-keto acid-dependent enzymes (28). Moreover, the BH4-dependent glyceryl-ether monooxygenase (GEM) also appears to be dependent on nonheme iron for catalysis (see also Section I.E). 

Kruger, H.-J. Iron-containing models of catechol dioxygenases, Biomimetic Oxidations Catalyzed by Transition Metal Complexes , Ed. Meunier, B. Imperial College Press London, 2000, pp. 363—413. 

These studies are part of a rare family of examples of the chemoselec-tive oxidation of catechols (150). The identification of the catalyst and the interception of the catalyst-dioxygen adduct are of particular relevance when the chemistry of catechol dioxygenase and tyrosinase enzymes is concerned. 

These two enzymes are also colorless and contain the ferrous form of iron90,91,94. The properties of catechol dioxygenases are summarized in Table 3. 

The nonheme iron-containing dioxygenases other than the catechol dioxygenases mentioned above are listed in Table 6. For the details of these enzymes, the readers are referred to the original references of individual enzymes or the review articles14,81. ... 

Table 6. Nonheme iron containing dioxygenases other than catechol dioxygenases listed in Table 3... 

The emphasis on the study of hemoproteins and the iron-sulfur proteins often distracts attention from other iron proteins where the iron is bound directly by the protein. A number of these proteins involve dimeric iron centres in which there is a bridging oxo group. These are found in hemerythrin (Section 62.1.12.3.7), the ribonucleotide reductases, uteroferrin and purple acid phosphatase. Another feature is the existence of a number of proteins in which the iron is bound by tyrosine ligands, such as the catechol dioxygenases (Section 62.1.12.10.1), uteroferrin and purple acid phosphatase, while a tyrosine radical is involved in ribonucleotide reductase. The catecholate siderophores also involve phenolic ligands (Section 62.1.11). Other relevant examples are transferrin and ferritin (Section 62.1.11). These iron proteins also often involve carboxylate and phosphate ligands. These proteins will be discussed in this section except for those relevant to other sections, as noted above. 

Figure 2.3 Molecular structure of [Fe(Me3TACN)(DBC)CI], a model complex for a catechol dioxygenase coordinated to its substrate molecule [28]. Hydrogen atoms have been omitted for clarity. The l,4,7-trimethyl-l,4,7-triazacyclononane (Me3TACN) ligand coordinates facially to the iron center. The remaining three coordination sites are occupied by 3,5-di-tert-butylcatecholate (DBC) and a chlorido ligand.

Figure 15 Proposed substrate activation mechanism for the intradiol cleaving catechol dioxygenases.

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