A Model for the Halogenating Agent of Chloroperoxidase*

DiNello, Robert K.; Rousseau, Kathleen; Dolphin, David

doi:10.1111/j.1749-6632.1975.tb41525.x

Cited by 8 publications

(6 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although we cannot explain the reason for such specificity, we have proposed a mechanism that is consistent with what is currently known concerning the active-site chemistry of chloride peroxidase. It has been proposed that the major resonant form of oxidized chloride peroxidase (Compound I) is a tetravalent iron porphyrin x-cation radical (IV), which is produced by the 2e oxidation of the native enzyme (Hager et al, 1975;DiNello et al, 1975). This structure for Compound I is analogous to that for the 'active oxygen' of cytochrome P-450 (Ullrich, 1977).…”

Section: Discussionmentioning

confidence: 98%

The action of chloride peroxidase on 4-chloroaniline. N-oxidation and ring halogenation

Corbett¹,

Chipko²,

Batchelor³

1980

Biochemical Journal

View full text Add to dashboard Cite

Chloride peroxidase catalyses both the ring halogenation and N-oxidation reactions of 4-chloroaniline by H2O2 and either KCl or KBr. In the absence of any halide salt only the N-oxidation reaction was observed, with the resulting conversion of 4-chloroaniline into 4-chloronitrosobenzene. The N-oxidation reaction proceeded even more rapidly in the presence of Cl- or Br-, in spite of the fact that ring halogenation was also a rapid reaction. The enhancement of N-oxidation was highly dependent on the pH of the media and displayed an optimum in the region of pH 3.5-4.0. No rate enhancement was observed above pH 5.5. KF partially inhibited the rate of N-oxidation in a pH-dependent manner. On the basis of calculated catalytic-centre activity the N-oxidation reaction was the major reaction at pH 3.5 or higher, whereas the ring-halogenation reaction became the major reaction below pH 3.5. In the presence of high concentrations of 4-chloroaniline relative to H2O2 the reaction intermediate, 4-chlorophenylhydroxylamine, was detected for the first time in a chloride peroxidase-catalysed reaction with this arylamine substrate. These findings were interpreted on the basis of current knowledge concerning the mechanism of action of chloride peroxidase.

show abstract

Section: Discussionmentioning

confidence: 98%

The action of chloride peroxidase on 4-chloroaniline. N-oxidation and ring halogenation

Corbett¹,

Chipko²,

Batchelor³

1980

Biochemical Journal

View full text Add to dashboard Cite

show abstract

“…However, to our surprise, atom-transfer reactions of isoporphyrin complexes with substrates, such as oxygenation and halogenation reactions, have not been well studied. 8 In this study, we show that an oxoiron(IV) porphyrin π-cation radical complex can be converted to iron(III) meso-chloro-isoporphyrin complex in the presence of trifluoroacetic acid (TFA) and chloride ion. Formation of the isoporphyrin complex would be due to protonations of the oxo ligand of oxoiron(IV) porphyrin π-cation radical species.…”

mentioning

confidence: 82%

“…Moreover, an unstable iron(III) isoporphyrin with a pyridinium group was reported to be formed from an iron(III) porphyrin π-cation radical complex with pyridine . On the other hand, iron(III) isoporphyrins have been proposed to be formed in reactions of heme enzymes. − The iron(III) isoporphyrin complex is two oxidation state equivalents higher than the iron(III) porphyrin complex. However, to our surprise, atom-transfer reactions of isoporphyrin complexes with substrates, such as oxygenation and halogenation reactions, have not been well studied .…”

mentioning

confidence: 99%

“…On the other hand, iron(III) isoporphyrins have been proposed to be formed in reactions of heme enzymes. − The iron(III) isoporphyrin complex is two oxidation state equivalents higher than the iron(III) porphyrin complex. However, to our surprise, atom-transfer reactions of isoporphyrin complexes with substrates, such as oxygenation and halogenation reactions, have not been well studied . In this study, we show that an oxoiron(IV) porphyrin π-cation radical complex can be converted to iron(III) meso -chloro-isoporphyrin complex in the presence of trifluoroacetic acid (TFA) and chloride ion.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Formation of Iron(III) meso-Chloro-isoporphyrin as a Reactive Chlorinating Agent from Oxoiron(IV) Porphyrin π-Cation Radical

2012

View full text Add to dashboard Cite

Iron(III) isoporphyrin, a tautomer of porphyrin with a saturated meso carbon, is one of the isoelectronic forms of oxoiron(IV) porphyrin π-cation radical, which is known as an important reactive intermediate of various heme enzymes. The isoporphyrin has been believed to be incapable of catalyzing oxygenation and oxidation reactions. Here, we report that an oxoiron(IV) porphyrin π-cation radical can be converted to iron(III) meso-chloro-isoporphyrin in the presence of trifluoroacetic acid and chloride ion. More importantly, this study shows the first evidence that iron(III) meso-chloro-isoporphyrin is an excellent reactive agent for chlorinating aromatic compounds and olefins. The results of this study suggest that the mechanism involves electrophilic chlorination of substrate with iron(III) meso-chloro-isoporphyrin.

show abstract

“…The tremendous difference between the aniline oxidation products resulting from chloroperoxidase and the other peroxidases can best be explained on the basis that the former generates ionic or nitreniumion reaction intermediates, whereas the peroxidases generate radical species. 4-Con'siderable evidence now suggests that the active site of chloroperoxidase Compound I is best represented as the tetravalent-iron porphyrin 7(cation radical (V) (Scheme 2) (Hager et al, 1975;DiNello et al, 1975;Loew et al, 1977). It has been proposed that the oxidative process occurs by electron transfer from a nucleophilic substrate to Compound I.…”

Section: Discussionmentioning

confidence: 99%

Chloroperoxidase-catalysed oxidation of 4-chloroaniline to 4-chloronitrosobenze

Corbett¹,

Chipko²,

Baden³

1978

Biochemical Journal

View full text Add to dashboard Cite

The incubation of 4-chloroaniline with chloroperoxidase and H2O2 resulted in a rapid formation of 4-chloronitrosobenzene. This enzymic oxidation displayed a pH optimum at 4.4 with a Km of 8.1x10(-4)M and catalytic-centre activity of 312. The initial rate of the reaction was strongly affected by the presence of halide ions. 4-Chlorophenylhydroxylamine was even more rapidly converted into the nitroso compound. A reaction mechanism is proposed on the basis of currently accepted theory for the catalytic action of chloroperoxidae. A noteworthy aspect of this new reaction is the difference in the products previously reported for the action of classical peroxidases on anilines and the single nitroso product resulting from chloroperoxidase oxidation.

show abstract

A Model for the Halogenating Agent of Chloroperoxidase*

Cited by 8 publications

References 9 publications

The action of chloride peroxidase on 4-chloroaniline. N-oxidation and ring halogenation

The action of chloride peroxidase on 4-chloroaniline. N-oxidation and ring halogenation

Formation of Iron(III) meso-Chloro-isoporphyrin as a Reactive Chlorinating Agent from Oxoiron(IV) Porphyrin π-Cation Radical

Chloroperoxidase-catalysed oxidation of 4-chloroaniline to 4-chloronitrosobenze

Contact Info

Product

Resources

About