Benzoate 2,3-dioxygenase

Benzoate dioxygenase (BZDO) Ralstonia eutropha (former Alcaligenes eutrophus) 1971 [236] [224]... 

Redox reaction for producing cis- 1,2-dihy-droxycatechol with benzoate dioxygenase from Pseudomonas putida multi t/y ICI [17]... 

Similar reactions were reported for the broad-substrate-specific benzoate dioxygenase of Rhodococcus sp. strain 19070[2G. Recombinant E. coli containing this enzyme transform benzoate and anthranilate to catechol and 2-hydro-l,2-dihydroxybenzoate, respectively. 

Aromatic compounds containing alkyl side chains are metabolized using three general strategies, illustrated in Figure 5. The first involves oxidation of the alkyl side chain toluene is oxidized to benzyl alcohol, and then further oxidized to benzaldehyde and benzoic acid. Benzoate dioxygenase then converts benzoate directly to catechol, via the corresponding air-diol. 

Fig. 3 Differences between dioxydation reactions catalyzed by TDO and benzoate dioxygenase (BZDO)...

Fig. 4 Catalytic metabolism of BZDO. BZDR benzoate dioxygenase reductase. (Lipscomb et al. 2002)...

Only the first two enzymes have received close attention. Each possesses one atom of ferric iron at the active site (2, 5J). The ascorbate S4) and chloromethylcatechol 85) dioxygenases also contain iron, but its oxidation state is unknown. Dihydroxyindole dioxygenase is probably a metallo-enzyme as it is inhibited by metal chelators (86). Dihydroxy-benzoate dioxygenase probably contains thiolate-bound metal as it is inhibited by sulfhydryl reagents (87). Analysis for co-factors has not yet been attempted for cafiTeate (88) and gallate (89) dioxygenases. 

SCHEME 32.2 Regio- and stereoselectivity of arene dihydroxylation by arene dioxygenases, (a) For TDO (toluene dioxygenase) and BPDO (biphenyl dioxygenase), (b) For BZDO (benzoate dioxygenase). 

BBE Berberine bridge enzyme BPDO Biphenyl dioxygenase BZDO Benzoate dioxygenase MAO Monoamine oxidase SAM S-adenosybnethionine SHC Squalene-hopene cyclase TDO Toluene dioxygenase... 

Rhizobia. Taxa belonging to both the genera Rhizobium and Bradyrhizobium are capable of degrading simple aromatic compounds including benzoate (Chen et al. 1984) and 4-hydroxy-benzoate (Parke and Omston 1986 Parke et al. 1991). It has been shown that 4-hydroxyben-zoate hydroxylase is required for the transport of 4-hydroxybenzoate into the cell (Wong et al. 1994). In strains of Rhizobium trifolium, the metabolism of benzoate involves either 3,4-dihydroxybenzoate (protocatechuate) 3,4-dioxygenase (Chen et al. 1984), or catechol... 

Neidle EL, C Hartnett, LN Ornmston, A Bairoch, M Rekin, S Harayama (1991) Nucleotide sequences of the Acinetobacter calcoaceticus benABC genes for benzoate 1,2-dioxygenase reveal evolutionary relationship among multicomponent oxygenases. J Bacteriol 173 5385-5395. 

Yamaguchi M, H Fujisawa (1982) Subunit structure of oxygenase components in benzoate 1,2-dioxygenase system from Pseudomonas arvilla C-1. J Biol Chem 257 12497-12502. 

Heavy-metal cations and oxyanions are generally toxic to bacteria although resistance may be induced by various mechanisms after exposure. Attention is drawn to an unusual example in which AF+ may be significant, since the catechol 1,2-dioxygenase and 3,4-dihydroxybenzoate (protocat-echuate) 3,4-dioxygenase that are involved in the metabolism of benzoate by strains of Rhizobium trifolii are highly sensitive to inhibition by AP (Chen et al. 1985). 

Degradation of PCBs is carried out by a suite of enzymes comprising biphenyl-2,3-dioxygenase, biphenyl-2,3-dihydrodiol dehydrogenase, 2,3-dihydroxybiphenyl dioxygenase, and the hydrolytic enzymes that produce benzoate encoded by the genes bphA, bphB, bphC, and bphD (Furukawa and Miyazaki 1986 Ahmad et al. 1991 Taira et al. 1992). 

Component B is a monomeric reductase with a molecular weight of 35,000 and contains per mol of enzyme, 1 mol of FMN, 2.1 mol of Fe, and 1.7 mol of labile sulfur. After reduction with NADH, the ESR spectrum showed signals that were attributed to a [2Fe-2S] structure and a flavo-semiquinone radical (Schweizer et al. 1987). The molecular and kinetic properties of the enzyme are broadly similar to the Class IB reductases of benzoate 1,2-dioxygenase and 4-methoxybenzoate monooxygenase-O-demethylase. 

Suzuki K, N Ogawa, K Miyashita (2001) Expression of 2-halobenzoate dioxygenase genes (cbdSABC) involved in the degradation of benzoate and 2-halobenzoate in Burkholderia sp. TH2. Gene 262 137-145. 

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