The ring cleaving enzyme 1H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase (HOD)) of Arthrobacter spec. R61a is part of the quinaldine degradation pathway. Carbon monoxide and N-acetyl-anthranilate are the products formed by dioxygenolytic cleavage of two C-C bonds in the substrate's pyridine ring. The gene coding for HOD was cloned and sequenced. An isoelectric point of pH 5.40 and a molecular mass of 31,838 Da was deduced from the sequence. HOD is shown to be remarkably similar to 1H-3-hydroxy-4-oxoquinoline 2,4-dioxygenase (QDO) of Pseudomonas putida 33/1, but not to other dioxygenases described so far. Consensus regions indicative for any chromophoric cofactor or any catalytically relevant metal were not detected. Sequence comparisons and secondary structure predictions revealed HOD as a new member of the alpha/beta hydrolase fold family. Expression in E. coli yielded recombinant catalytically active His-tagged HOD. S101A and D233A, two mutants of HOD, were obtained by site-directed mutagenesis. Since their residual activity is 43.1% and 62.6%, respectively, they probably are of no catalytic relevance although they might play a role in the interaction between enzyme and substrate.
Title: Cloning, sequence analysis, and expression of the Pseudomonas putida 33/1 1H-3-hydroxy-4-oxoquinoline 2,4-dioxygenase gene, encoding a carbon monoxide forming dioxygenase Max N, Betz A, Facey S, Lingens F, Hauer B, Fetzner S Ref: Biochimica & Biophysica Acta, 1431:547, 1999 : PubMed
1H-3-hydroxy-4-oxoquinoline 2,4-dioxygenase (Qdo) from the 1H-4-oxoquinoline utilizing Pseudomonas putida strain 33/1, which catalyzes the cleavage of 1H-3-hydroxy-4-oxoquinoline to carbon monoxide and N-formylanthranilate, is devoid of any transition metal ion or other cofactor and thus represents a novel type of ring-cleavage dioxygenase. Gene qdo was cloned and sequenced. Its overexpression in Escherichia coli yielded recombinant His-tagged Qdo which was catalytically active. Qdo exhibited 36% and 16% amino acid identity to 1H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase (Hod) and atropinesterase (a serine hydrolase), respectively. Qdo as well as Hod possesses a SXSHG motif, resembling the motif GXSXG of the serine hydrolases which comprises the active-site nucleophile (X=arbitrary residue).
Title: 2-oxo-1,2-dihydroquinoline 8-monooxygenase: phylogenetic relationship to other multicomponent nonheme iron oxygenases Rosche B, Tshisuaka B, Hauer B, Lingens F, Fetzner S Ref: Journal of Bacteriology, 179:3549, 1997 : PubMed
2-Oxo-1,2-dihydroquinoline 8-monooxygenase, an enzyme involved in quinoline degradation by Pseudomonas putida 86, had been identified as a class IB two-component nonheme iron oxygenase based on its biochemical and biophysical properties (B. Rosche, B. Tshisuaka, S. Fetzner, and F. Lingens, J. Biol. Chem. 270:17836-17842, 1995). The genes oxoR and oxoO, encoding the reductase and the oxygenase components of the enzyme, were sequenced and analyzed. oxoR was localized approximately 15 kb downstream of oxoO. Expression of both genes was detected in a recombinant Pseudomonas strain. In the deduced amino acid sequence of the NADH:(acceptor) reductase component (OxoR, 342 amino acids), putative binding sites for a chloroplast-type [2Fe-2S] center, for flavin adenine dinucleotide, and for NAD were identified. The arrangement of these cofactor binding sites is conserved in all known class IB reductases. A dendrogram of reductases confirmed the similarity of OxoR to other class IB reductases. The oxygenase component (OxoO, 446 amino acids) harbors the conserved amino acid motifs proposed to bind the Rieske-type [2Fe-2S] cluster and the mononuclear iron. In contrast to known class IB oxygenase components, which are composed of differing subunits, OxoO is a homomultimer, which is typical for class IA oxygenases. Sequence comparison of oxygenases indeed revealed that OxoO is more related to class IA than to class IB oxygenases. Thus, 2-oxo-1,2-dihydroquinoline 8-monooxygenase consists of a class IB-like reductase and a class IA-like oxygenase. These results support the hypothesis that multicomponent enzymes may be composed of modular elements having different phylogenetic origins.
Title: 2,4-dioxygenases catalyzing N-heterocyclic-ring cleavage and formation of carbon monoxide. Purification and some properties of 1H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase from Arthrobacter sp. Ru61a and comparison with 1H-3-hydroxy-4-oxoquinoline 2,4-dioxygenase from Pseudomonas putida 33/1 Bauer I, Max N, Fetzner S, Lingens F Ref: European Journal of Biochemistry, 240:576, 1996 : PubMed
1H-3-Hydroxy-4-oxoquinaldine 2,4-dioxygenase (MeQDO) was purified from quinaldine-grown Arthrobacter sp. Ru61a. It was enriched 59-fold in a yield of 22%, and its properties were compared with 1H-3-hydroxy-4-oxoquinoline 2,4-dioxygenase (QDO) purified from Pseudomonas putida 33/1. The enzyme-catalyzed conversions were performed in an (18O)O2/(16O)O2 atmosphere. Two oxygen atoms of either (18O)O2 or (16O)O2 were incorporated at C2 and C4 of the respective substrates, indicating that these unusual enzymes, which catalyze the cleavage of two carbon-carbon bonds concomitant with CO formation, indeed are 2,4-dioxygenases. Both enzymes are small monomeric proteins of 32 kDa (MeQDO) and 30 kDa (QDO). The apparent K(m) values of MeQDO for 1H-3-hydroxy-4-oxoquinaldine and QDO for 1H-3-hydroxy-4-oxoquinoline were 30 microM and 24 microM, respectively. In both 2,4-dioxygenases, there was no spectral evidence for the presence of a chromophoric cofactor. EPR analyses of MeQDO did not reveal any signal that could be assigned to an organic radical species or to a metal, and X-ray fluorescence spectrometry of both enzymes did not show any metal present in stoichiometric amounts. Ethylxanthate, metal-chelating agents (tiron, alpha, alpha'-bipyridyl, 8-hydroxyquinoline, o-phenanthroline, EDTA, diphenylthiocarbazone, diethyldithiocarbamate), reagents that modify sulfhydryl groups (iodoacetamide, N-ethylmaleimide, p-hydroxymercuribenzoate), and reducing agents (sodium dithionite, dithiothreitol, mercaptoethanol) either did not affect 2,4-dioxygenolytic activities at all or inhibited at high concentrations only. With respect to the supposed lack of any cofactor and with respect to the inhibitors of dioxygenolytic activities, MeQDO and QDO resemble aci-reductone oxidase (CO-forming) from Klebsiella pneumoniae, which catalyzes 1,3-dioxygenolytic cleavage of 1,2-dihydroxy-3-keto-S-methylthiopentene anion (Wray, J. W. & Abeles, R. H. (1993) J. Biol. Chem. 268, 21466-21469; Wray, J. W. & Abeles, R. H. (1995) J. Biol. Chem. 270, 3147-3153). 1H-3-Hydroxy-4-oxoquinaldine and 1H-3-hydroxy-4-oxoquinoline were reactive towards molecular oxygen in the presence of the base catalyst potassium-tert.-butoxide in the aprotic solvent N,N-dimethylformamide. Base-catalyzed oxidation, yielding the same products as the enzyme-catalyzed conversions, provides a non-enzymic model reaction for 2,4-dioxygenolytic release of CO from 1H-3-hydroxy-4-oxoquinaldine and 1H-3-hydroxy-4-oxoquinoline.
Title: The catechol 2,3-dioxygenase gene of Rhodococcus rhodochrous CTM: nucleotide sequence, comparison with isofunctional dioxygenases and evidence for an active-site histidine Candidus S, van Pee KH, Lingens F Ref: Microbiology, 140:321, 1994 : PubMed
In cell-free extracts of Escherichia coli clones harbouring the 3.5 kb Bg/II fragment of plasmid pTC1 from Rhodococcus rhodochrous CTM a catechol 2,3-dioxygenase (C23O) accepting both 3-methylcatechol and 2,3-dihydroxybiphenyl as substrates could be detected. The plasmid-encoded gene for C23O of R. rhodochrous CTM and its flanking regions were sequenced. In front of the gene a sequence resembling an E. coli promoter was identified, which led to constitutive expression of the cloned gene in E. coli TG1. The derived amino acid sequence of the C23O was compared to that of nine other enzymes, which all catalyse the extradiol cleavage of an aromatic ring. These nine sequences were from different Pseudomonas strains, in contrast to the sequence described here, from a Gram-positive bacterium. The role of four strongly conserved histidines was examined by chemical modification of the histidyl residues of the native enzyme by diethylpyrocarbonate. For that purpose the C23O was purified to homogeneity from E. coli harbouring pSC1701. However, the enzyme lost its activity during the purification. Activity could partially be restored by treatment with Fe2+ and reducing agents.
Title: Bacterial dehalogenases: biochemistry, genetics, and biotechnological applications Fetzner S, Lingens F Ref: Microbiol Rev, 58:641, 1994 : PubMed
This review is a survey of bacterial dehalogenases that catalyze the cleavage of halogen substituents from haloaromatics, haloalkanes, haloalcohols, and haloalkanoic acids. Concerning the enzymatic cleavage of the carbon-halogen bond, seven mechanisms of dehalogenation are known, namely, reductive, oxygenolytic, hydrolytic, and thiolytic dehalogenation; intramolecular nucleophilic displacement; dehydrohalogenation; and hydration. Spontaneous dehalogenation reactions may occur as a result of chemical decomposition of unstable primary products of an unassociated enzyme reaction, and fortuitous dehalogenation can result from the action of broad-specificity enzymes converting halogenated analogs of their natural substrate. Reductive dehalogenation either is catalyzed by a specific dehalogenase or may be mediated by free or enzyme-bound transition metal cofactors (porphyrins, corrins). Desulfomonile tiedjei DCB-1 couples energy conservation to a reductive dechlorination reaction. The biochemistry and genetics of oxygenolytic and hydrolytic haloaromatic dehalogenases are discussed. Concerning the haloalkanes, oxygenases, glutathione S-transferases, halidohydrolases, and dehydrohalogenases are involved in the dehalogenation of different haloalkane compounds. The epoxide-forming halohydrin hydrogen halide lyases form a distinct class of dehalogenases. The dehalogenation of alpha-halosubstituted alkanoic acids is catalyzed by halidohydrolases, which, according to their substrate and inhibitor specificity and mode of product formation, are placed into distinct mechanistic groups. beta-Halosubstituted alkanoic acids are dehalogenated by halidohydrolases acting on the coenzyme A ester of the beta-haloalkanoic acid. Microbial systems offer a versatile potential for biotechnological applications. Because of their enantiomer selectivity, some dehalogenases are used as industrial biocatalysts for the synthesis of chiral compounds. The application of dehalogenases or bacterial strains in environmental protection technologies is discussed in detail.
Title: Chloroperoxidase-encoding gene from Pseudomonas pyrrocinia: sequence, expression in heterologous hosts, and purification of the enzyme Wolfframm C, Lingens F, Mutzel R, van Pee KH Ref: Gene, 130:131, 1993 : PubMed
The nucleotide sequence of a 1.5-kb fragment of Pseudomonas pyrrocinia DNA containing the chloroperoxidase(CPO)-encoding gene (cpo) and its flanking regions was determined. The cpo codes for a protein of 278 amino acids (aa). The mature enzyme contains no N-terminal methionine, so that the CPO monomer consists of 277 aa with a calculated M(r) of 30,304. Expression studies showed that the cpo from P. pyrrocinia is functionally expressed in Escherichia coli and Streptomyces lividans. Based on the overproduction of the CPO in E. coli, a novel and simple purification procedure was developed allowing the isolation of about 800-fold more CPO per gram of cells than was originally isolated from P. pyrrocinia. Comparison with the aa sequence of the bromoperoxidase BPO-A2 from S. aureofaciens ATCC10762 revealed an identity of 38%.
Title: Microbial metabolism of quinoline and related compounds. XIV. Purification and properties of 1H-3-hydroxy-4-oxoquinoline oxygenase, a new extradiol cleavage enzyme from Pseudomonas putida strain 33/1 Block DW, Lingens F Ref: Biol Chem Hoppe Seyler, 373:343, 1992 : PubMed
1H-3-Hydroxy-4-oxoquinoline oxygenase was purified to apparent homogeneity from Pseudomonas putida strain 33/1 which can use 1H-4-oxoquinoline as sole source of carbon. The molecular mass of the enzyme was determined to 26,000 Da by gel chromatography and by SDS polyacrylamide gel electrophoresis. The enzyme is labile at temperatures above 30 degrees C and has a pH optimum of 8.0. It requires oxygen for the reaction and is significantly inhibited by metal ions like Cu2+, Zn2+, Hg2+ and by 4-chloromercuribenzoate. The enzyme is specific only for 1H-3-Hydroxy-4-oxoquinoline; the apparent Km value for this substrate is 24 microM.
Bromoperoxidase from Streptomyces aureofaciens ATCC 10762, a non-haem haloperoxidase, has been crystallized using the hanging drop method. Preliminary X-ray diffraction studies show that the crystals belong to the cubic space group P2(1)3 with a = 123.4 A. The asymmetric unit contains a dimer of Mr = 60,200. The crystals diffract to at least 2.3 A resolution and are suitable for crystallographic structure analysis.
Title: Purification, characterization and comparison of two non-haem bromoperoxidases from Streptomyces aureofaciens ATCC 10762 Weng M, Pfeifer O, Krauss S, Lingens F, van Pee KH Ref: J Gen Microbiol, 137:2539, 1991 : PubMed
Two non-haem bromoperoxidases (BPO 1 and BPO 2) were purified from the 7-chlorotetracycline-producing strain Streptomyces aureofaciens ATCC 10762. Both enzymes showed azide-insensitive brominating activity, and bromide-dependent peroxidase activity. BPO 1 was a dimer (Mr 65,000) with subunits of identical size (Mr 31,000). The pI was estimated to be 4.5. The enzyme did not cross-react with antibodies raised against the non-haem bromoperoxidase (Mr 90,000) from S. aureofaciens Tu24, a strain that also produces 7-chlorotetracycline. The Mr of BPO 2 was estimated to be 90,000. The enzyme had three identical subunits (Mr 31,000), and its isoelectric point was 3.5, identical with that of the bromoperoxidase from S. aureofaciens Tu24. Moreover, BPO 2 was immunologically identical with the bromoperoxidase from S. aureofaciens Tu24, although both it and BPO 1 could be distinguished electrophoretically from the latter bromoperoxidase.
Title: Purification, properties and immunological detection of a bromoperoxidase-catalase from Streptomyces venezuelae and from a chloramphenicol-nonproducing mutant Knoch M, van Pee KH, Vining LC, Lingens F Ref: J Gen Microbiol, 135:2493, 1989 : PubMed
A new bromoperoxidase-catalase was purified from the chloramphenicol-producing actinomycete Streptomyces venezuelae ISP 5230. The homogeneous enzyme showed brominating activity, catalase activity and a very low peroxidase activity. The spectral properties and pH dependence of the catalase activity showed similarities to conventional catalases. In contrast to other haem-bromoperoxidases, the bromoperoxidase-catalase was stable when treated with an ethanol/chloroform mixture. Gel filtration gave an estimated Mr of 127,000-136,000. SDS-PAGE showed a single band corresponding in mobility to a species with an Mr of 61,000. The pI was estimated to be 4.5. The bromoperoxidase-catalase was not present in active form in a mutant of S. venezuelae ISP 5230, blocked in the chlorination step of chloramphenicol biosynthesis. However, an inactive species of the enzyme was detected in crude extracts of the mutant by using antibodies. From these results it is concluded that this bromoperoxidase participates in the chlorination step during chloramphenicol biosynthesis.
Title: Purification and characterization of a novel bacterial non-heme chloroperoxidase from Pseudomonas pyrrocinia Wiesner W, van Pee KH, Lingens F Ref: Journal of Biological Chemistry, 263:13725, 1988 : PubMed
The first bacterial chloroperoxidase that is capable of catalyzing the chlorination of indole to 7-chloroindole was detected in Pseudomonas pyrrocinia ATCC 15958, a bacterium that produces the antifungal antibiotic pyrrolnitrin (Wiesner, W., van Pe, K.H., and Lingens, F. (1986) FEBS Lett. 209, 321-324). Here we describe the purification and characterization of this bacterial non-heme chloroperoxidase. The enzyme was purified by DEAE-cellulose chromatography at different pH values, molecular sieve chromatography, and Bio-Gel HTP hydroxylapatite. After the last purification step, chloroperoxidase was homogeneous by polyacrylamide gel electrophoresis and ultracentrifugation. Based on gel filtration and ultracentrifugation results, the molecular weight of the enzyme was 64,000 +/- 3,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a single band with the mobility of a 32,000 molecular weight species. Therefore, in solution at neutral pH, this chloroperoxidase is a dimer. The enzyme did not exhibit any absorbance in the visible region of the spectrum. The isoelectric point was 4.1. Chloroperoxidase was specific for I-, Br-, and Cl- and was not inhibited by azide, but was inhibited by cyanide and F-. This procaryotic chloroperoxidase catalyzed the bromination of monochlorodimedone but not its chlorination and has no peroxidase or catalase activity. The pH optimum of the enzyme was between 4.0 and 4.5, and the enzyme was stable between pH 3.5 and 8.5 and showed no loss of activity when incubated at 60 degrees C for 2 h. Chloroperoxidase also chlorinated 4-(2-amino-3-chlorophenyl) pyrrole to yield aminopyrrolnitrin, the immediate precursor of pyrrolnitrin. This suggests very strongly that chloroperoxidase is involved in the biosynthesis of the antibiotic pyrrolnitrin.
Title: Cloning and high-level expression of a chloroperoxidase gene from Pseudomonas pyrrocinia in Escherichia coli Wolfframm C, van Pee KH, Lingens F Ref: FEBS Letters, 238:325, 1988 : PubMed
A chloroperoxidase gene from Pseudomonas pyrrocinia was cloned into Escherichia coli using the cosmid vector pJB8. The gene coding for the chloroperoxidase could be localized to a 1.5 kb fragment of DNA which was subcloned into the high-copy-number plasmid pUC18. In one subclone increased halogenating activity could be found which was 570-fold greater than in P. pyrrocinia. The halogenating enzyme was identified as the chloroperoxidase by SDS-polyacrylamide gel electrophoresis.
Title: Purification and partial characterization of multiple bromoperoxidases from Streptomyces griseus Zeiner R, van Pee KH, Lingens F Ref: J Gen Microbiol, 134:3141, 1988 : PubMed
The presence of multiple bromoperoxidases in extracts of Streptomyces griseus T 6 was detected. The enzyme pattern varied with the age of the culture. A haem-type bromoperoxidase (BPO 2) was always present. Additionally three nonhaem-type bromoperoxidases (BPO 1a, 1b and 3) were detected and purified to homogeneity. The Mr of non-denatured BPO 1a was 70,000 +/- 10,000 and those of BPO 1b and 3 were 90,000 +/- 5000. BPO 1a and 1b were dimers with subunit Mr values of 34,000 and 43,000, respectively. BPO 3 was a trimer with a subunit Mr of 31,000. The enzymes differed in their isoelectric points, heat stability, and Km values. In immunodiffusion experiments BPO 1a and 3 showed partial identity with the nonhaem-type bromoperoxidase from Streptomyces aureofaciens. The nonhaem-type BPO 1a, 1b and 3 had neither peroxidase nor catalase activity.
Title: Purification and properties of a nonheme bromoperoxidase from Streptomyces aureofaciens van Pee KH, Sury G, Lingens F Ref: Biol Chem Hoppe Seyler, 368:1225, 1987 : PubMed
The first bacterial nonheme type bromoperoxidase has been purified to homogeneity from the chlorotetracycline-producing actinomycete Streptomyces aureofaciens T 24. Purification was accomplished by (NH4)2SO4 precipitation, DEAE-cellulose chromatography at different pH-values, and molecular sieve chromatography. The purified enzyme has a molecular mass of 90 to 95 kDa based on ultracentrifugation and gel filtration. The enzyme is composed of three subunits of identical molecular mass (m = 31 kDa). Bromoperoxidase catalyses the bromination of monochlorodimedone, but not its chlorination, and has no peroxidase or catalase activity. The optimum pH is 4.5. The enzyme does not exhibit an absorption peak in the Soret region of the optical spectrum. X-ray fluorescence spectroscopy revealed that the enzyme does not contain any metals in equimolar amounts. Bromoperoxidase is stable in a pH range from pH 4.0 to pH 10.0 at 4 degrees C for weeks and does not loose any activity when incubated at 80 degrees C for 2 h.
Title: Detection of a new chloroperoxidase in Pseudomonas pyrrocinia Wiesner W, van Pee KH, Lingens F Ref: FEBS Letters, 209:321, 1986 : PubMed
A new chloroperoxidase could be detected in Pseudomonas pyrrocinia ATCC 15,958, a bacterium that produces the antifungal antibiotic pyrrolnitrin. This enzyme was separated from a ferriprotoporphyrin IX containing bromoperoxidase which was also produced by this bacterium. The enzyme is capable of catalyzing the chorination of indole to 7-chloroindole. This procaryotic chloroperoxidase requires the presence of H2O2 and can also brominate monochlorodimedone, but cannot catalyze its chlorination. This enzyme is the first chloroperoxidase described from procaryotic sources.
Title: Purification and properties of bromoperoxidase from Pseudomonas pyrrocinia Wiesner W, van Pee KH, Lingens F Ref: Biol Chem Hoppe Seyler, 366:1085, 1985 : PubMed
A bromoperoxidase was purified and partially characterized from Pseudomonas pyrrocinia ATCC 15958, a bacterium that produces the antifungal antibiotic pyrrolnitrin. The purified enzyme preparation was homogeneous as determined by polyacrylamide gel electrophoresis and ultracentrifugation. The molecular mass of the enzyme was estimated to be 154 kDa +/- 3 kDa as determined by gel filtration and ultracentrifugation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed a single band with the mobility of a 76-kDa species. Therefore, in solution at neutral pH, bromoperoxidase exists as a dimeric species. The isoelectric point was 5.0. The prosthetic group of this procaryotic bromoperoxidase was ferriprotoporphyrin IX. The spectral properties of the native and reduced enzyme are reported. The purified enzyme showed brominating as well as peroxidase and catalase activity.
Title: Purification of bromoperoxidase from Pseudomonas aureofaciens van Pee KH, Lingens F Ref: Journal of Bacteriology, 161:1171, 1985 : PubMed
A Bromoperoxidase has been isolated and purified from Pseudomonas aureofaciens ATCC 15926 mutant strain ACN. The purified enzyme was homogeneous as determined by polyacrylamide gel electrophoresis and ultracentrifugation. This bromoperoxidase can utilize bromide ions in the presence of hydrogen peroxide and a halogen acceptor for the catalytic formation of carbon-halogen bonds. The homogeneous enzyme also has peroxidase and catalase activity. Based on the results from gel filtration and ultracentrifugation, the molecular weight of this procaryotic bromoperoxidase is 155,000 to 158,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows a single band having the mobility of a 77,000-molecular-weight species. We thus conclude that this bromoperoxidase exists in solution as a dimeric species. The heme prosthetic group of bromoperoxidase is ferriprotoporphyrin IX. The spectral properties of the native and reduced enzyme are reported. This bromoperoxidase is the first halogenating enzyme purified from procaryotic sources.
Title: Purification and molecular and catalytic properties of bromoperoxidase from Streptomyces phaeochromogenes van Pee KH, Lingens F Ref: J Gen Microbiol, 131:1911, 1985 : PubMed
A bromoperoxidase has been isolated and purified from the chloramphenicol-producing actinomycete Streptomyces phaeochromogenes. The purified enzyme was homogeneous as determined by polyacrylamide gel electrophoresis. The prosthetic group of the bromoperoxidase was ferriprotoporphyrin IX. Based on gel filtration results the molecular weight of the enzyme was 147 000 +/- 3000. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed a single band having the mobility of a 72 500 molecular weight species. Therefore, in solution at neutral pH, the bromoperoxidase behaved as a dimer. The isoelectric point was 4.0. The spectral properties of the native and reduced enzyme are reported. The homogeneous enzyme also had peroxidase and catalase activity.
Title: Detection of a bromoperoxidase in Streptomyces phaeochromogenes van Pee KH, Lingens F Ref: FEBS Letters, 173:5, 1984 : PubMed
A bromoperoxidase could be detected after fractionation in the chloramphenicol producing actinomycete, Streptomyces phaeochromogenes. This enzyme is capable of catalyzing the bromination of the antifungal antibiotic pyrrolnitrin [3-chloro-4-(2-nitro-3-chlorophenyl)pyrrole] in the 2-position of the pyrrole ring. The enzyme had a pH optimum of 5.0. This procaryotic bromoperoxidase requires the presence of H2O2 and can also brominate monochlorodimedone, but cannot catalyze chlorination. This enzyme is the first haloperoxidase described from procaryotic sources.
