Horseradish peroxidase compound I: evidence for spin coupling between the heme iron and a ‘free’ radical

Schulz, Charles E.; Devaney, P.W.; Winkler, H.; Debrunner, Peter G.; Doan, N. B.; Chiang, R.; Rutter, Rick; Hager, Lowell P.

doi:10.1016/0014-5793(79)81259-4

Cited by 235 publications

(196 citation statements)

References 16 publications

Supporting

Mentioning

173

Contrasting

Order By: Relevance

“…It is of note that the magnetic interaction (ferromagnetic exchange coupling) between the porphyrin -cation radical (Por ⅐ ϩ ) and the oxoferryl (Fe(IV)ϭO) moiety is at the origin of the broad and axial EPR spectrum for the compound I intermediate (27). Accordingly, the previously reported EPR spectrum of the compound I intermediate in E. coli HPI catalaseperoxidase (8) would be consistent with the g ʈ ϭ 2 component of the broad signal.…”

Section: Epr Spectrum Of Compound I-mentioning

confidence: 61%

Total Conversion of Bifunctional Catalase-Peroxidase (KatG) to Monofunctional Peroxidase by Exchange of a Conserved Distal Side Tyrosine

Jakopitsch

Auer

Ivancich

et al. 2003

Journal of Biological Chemistry

111

View full text Add to dashboard Cite

show abstract

Section: Epr Spectrum Of Compound I-mentioning

confidence: 61%

Total Conversion of Bifunctional Catalase-Peroxidase (KatG) to Monofunctional Peroxidase by Exchange of a Conserved Distal Side Tyrosine

Jakopitsch

Auer

Ivancich

et al. 2003

Journal of Biological Chemistry

111

View full text Add to dashboard Cite

show abstract

“…Moreover, one expects AgdI > bg I I I 0 for a planar -r radical, contrary to observation for ES (22). Finally, through calulations such as those of Schulz et al (23) one may show that spin-coupling between the S = 1 heme and a radical cannot produce the observed g values. The g values of ES are consistent with those of a peroxy radical (12).…”

Section: Methodsmentioning

confidence: 78%

Electron-nuclear double resonance of the hydrogen peroxide compound of cytochrome c peroxidase: identification of the free radical site with a methionyl cluster.

Hoffman¹,

Roberts²,

Brown³

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The results of electron-nuclear double resonance and electron paramagnetic resonance (EPR) studies on the hydrogen peroxide compound of yeast cytochrome c peroxidase are inconsistent with previous proposals for the source of the EPR signal in this compound, in particular with its identification with an aromatic amino acid radical such as would arise by oxidation of a tryptophanyl side chain. The present observations lead us to propose that the EPR signal is associated with a cluster containing at least one methionine and in which proximate side chains share the charge created by loss of one electron.

show abstract

“…In contrast to that of the parent enzyme, the F221W mutant exhibited a rather sharp EPR signal at g ʈ ϭ 2.036 and g Ќ ϭ 2.007 (Fig. 3, b and c), characteristic of the Trp radical in CcP compound I (g ʈ ϭ 2.037 and g Ќ ϭ 2.005) (23)(24)(25). Although we have not yet succeeded in the quantitative analysis for the EPR measurements after mixing the mutant with hydrogen peroxide, the second reaction intermediate in which the Soret peak appeared at 419 nm seems to afford these EPR signals characteristic of the Trp radical.…”

Section: Resultsmentioning

confidence: 97%

Detection of a Tryptophan Radical as an Intermediate Species in the Reaction of Horseradish Peroxidase Mutant (Phe-221 → Trp) and Hydrogen Peroxide

Morimoto¹,

Tanaka²,

Takahashi³

et al. 1998

Journal of Biological Chemistry

View full text Add to dashboard Cite

The crucial reaction intermediate in the reaction of peroxidase with hydrogen peroxide (H 2 O 2 ), compound I, contains a porphyrin -cation radical in horseradish peroxidase (HRP), which catalyzes oxidation of small organic and inorganic compounds, whereas cytochrome c peroxidase (CcP) has a radical center on the tryptophan residue (Trp-191) and oxidizes the redox partner, cytochrome c. To investigate the roles of the amino acid residue near the heme active center in discriminating the function of the peroxidases in these two enzymes, we prepared a CcP-like HRP mutant, F221W (Phe-221 3 Trp). Although the rapid spectral scanning and stoppedflow experiments confirmed that the F221W mutant reacts with H 2 O 2 to form the porphyrin -cation radical at the same rate as for the wild-type enzyme, the characteristic spectral features of the porphyrin -cation radical disappeared rapidly, and were converted to the compound II-type spectrum. The EPR spectrum of the resultant species produced by reduction of the porphyrin -cation radical, however, was quite different from that of compound II in HRP, showing typical signals from a Trp radical as found for CcP. The sequential radical formation from the porphyrin ring to the Trp residue implies that the proximal Trp is a key residue in the process of the radical transfer from the porphyrin ring, which differentiates the function of peroxidases.

show abstract

Horseradish peroxidase compound I: evidence for spin coupling between the heme iron and a ‘free’ radical

Cited by 235 publications

References 16 publications

Total Conversion of Bifunctional Catalase-Peroxidase (KatG) to Monofunctional Peroxidase by Exchange of a Conserved Distal Side Tyrosine

Total Conversion of Bifunctional Catalase-Peroxidase (KatG) to Monofunctional Peroxidase by Exchange of a Conserved Distal Side Tyrosine

Electron-nuclear double resonance of the hydrogen peroxide compound of cytochrome c peroxidase: identification of the free radical site with a methionyl cluster.

Detection of a Tryptophan Radical as an Intermediate Species in the Reaction of Horseradish Peroxidase Mutant (Phe-221 → Trp) and Hydrogen Peroxide

Contact Info

Product

Resources

About