Preparation and characterisation of iron(IV) porphyrin in aqueous solution at room temperature: a proposed model for peroxidase compound II

Shedbalkar, V. P.; Modi, Sandeep; Mitra, Samaresh

doi:10.1039/c39880001238

Cited by 8 publications

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“…In classical peroxidase reaction the oxidation of substrates generally proceeds through two oxo-ferryl intermediates, called Compound I and Compound II, which are two and one oxidizing equivalents, respectively, above the Fe(III) state (Dawson 1988). Hemoglobin (Smith and Beck 1967), myoglobin (Kelman et al 1994), cyt c (Vazquez-Duhalt 1999), heme peptide microperoxidase (Casella et al 2000) and heme c (Shedbalkar et al 1988) show peroxidase-like activity similar to classical peroxidases, though their reactivities with hydrogen peroxide are quite different. Although cyt c is a sluggish catalase/peroxidase, it can be physiologically relevant due to its high in vivo concentration (Belikova et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Rate of oxidative modification of cytochrome c by hydrogen peroxide is modulated by Hofmeister anions

Tomášková¹,

Varinská²,

Sedlák³

2010

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Cytochrome c (cyt c) and other heme proteins are oxidatively modified in the presence of hydrogen peroxide in a concentration-and time-dependent manner. Cyt c modification has been monitored by several spectral probes by absorption spectroscopy (at wavelengths 410 nm, 530 nm), and circular dichroism (222, 268, 288 and 417 nm). Kinetics monitored with these spectral probes indicates that the oxidative modification of cyt c: i) proceeds in the order: heme → aromatic amino acids → secondary structure, and ii) the rate of the oxidative modification is proportional to the protein flexibility. The flexibility of cyt c was modulated by anions of Hofmeister series (sulfate, chloride, perchlorate) (Varhač et al. 2009). A minimalist scheme of the interaction of cyt c with hydrogen peroxide can be described by two steps: 1) interaction of hydrogen peroxide with heme iron forming the postulated ferryl intermediate, 2a) oxidation of another molecule of hydrogen peroxide and 2b) parallel oxidation of close amino acid residue(s) and/or heme. The catalase activity of cyt c is independent from the presence of Hofmeister anions, which indicates that both steps (1 and 2a) in the catalase reaction are independent from the flexibility of the heme region of the protein matrix. On the other hand, the flexibility of the polypeptide chain of the protein modulates the rate of parallel oxidative modification of the heme and amino acid residues.

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Section: Introductionmentioning

confidence: 99%

Rate of oxidative modification of cytochrome c by hydrogen peroxide is modulated by Hofmeister anions

Tomášková¹,

Varinská²,

Sedlák³

2010

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“…The extended π-orbital network of these macromolecules also leads to applications in electronics and solid-state chemistry. Particularly, porphyrin derivatives play a crucial role in many chemical and biological electron-transfer reactions [ 901 ]; these include iron(IV) porphyrin as a model for the peroxidases [ 903 ].…”

Section: Addendamentioning

confidence: 99%

New chemical and stereochemical applications of organoiron complexes

Fatiadi

1991

J. RES. NATL. INST. STAN.

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The objective of this review is to provide a current overview of the rapidly developing chemistry of organometallic complexes and particularly organoiron complexes useful in asymmetric and stereoselective reactions. Also covered are stereoselective reactions of α, β-unsaturated acyl ligands bound to the chiral auxiliary [(η5-C5H5) Fe(CO)(PPh3)] and new applications of organoiron complexes in the synthesis of natural products. The mechanistic aspects and stabilizing effects of the Fe(CO)3 group for alkenes or conjugated dienes are discussed. A brief summary of recent work on the special role of iron in biological reactions is also included.

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“…The oxoferryl group Fe IV O is believed to be a reaction intermediate in the mechanism of action of peroxidases, oxygen transfer species in cytochrome P-450, and autoxidation of Fe(II) porphyrins . Several groups have reported the formation of iron(IV) oxo−porphyrin complexes by chemical, photochemical, and electrochemical methods at low temperatures and characterized them by various techniques. − On the other hand, room-temperature stabilization and characterization of the oxoferryl species in only a few synthetic porphyrins and natural enzyme systems like myoglobin and peroxidases have been reported in the recent past. 6b,− Table gives the Fe IV O stretching and other relevant Raman frequencies for some selected systems. However, we have not come across any report of oxoferryl species of simple iron tetraphenylporphyrins having been observed in aqueous systems at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Resonance Raman Characterization of (Oxoferryl)tetraphenylporphyrin Formed during Photodisproportionation of (Fe(TPP))₂O in a Detergent Micelle at Room Temperature

Shantha

Verma

1996

Inorg. Chem.

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We report the formation and characterization of (oxoferryl)tetraphenylporphyrin ((TPP)FeIVO) as a result of photodisproportionation of the μ-oxo dimer, (Fe(TPP))2O, obtained on solubilization of Fe(TPP)Cl in an aqueous alkaline TX-100 detergent micelle, under 441.6 nm laser excitation at room temperature and at −50 °C. The other photoproduct is identified as a five-coordinated, high-spin (5cHS) ferrous complex.

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Preparation and characterisation of iron(IV) porphyrin in aqueous solution at room temperature: a proposed model for peroxidase compound II

Abstract: By use of porphyrin C as ligand, the FelV state has been stabilised in aqueous solution at room temperature for the first time, and characterised by optical spectroscopy, 1H n.m.r., e.s.r., and magnetic moment measurements.

Cited by 8 publications

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Rate of oxidative modification of cytochrome c by hydrogen peroxide is modulated by Hofmeister anions

Rate of oxidative modification of cytochrome c by hydrogen peroxide is modulated by Hofmeister anions

New chemical and stereochemical applications of organoiron complexes

Resonance Raman Characterization of (Oxoferryl)tetraphenylporphyrin Formed during Photodisproportionation of (Fe(TPP))₂O in a Detergent Micelle at Room Temperature

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Preparation and characterisation of iron(IV) porphyrin in aqueous solution at room temperature: a proposed model for peroxidase compound II

Abstract: By use of porphyrin C as ligand, the FelV state has been stabilised in aqueous solution at room temperature for the first time, and characterised by optical spectroscopy, 1H n.m.r., e.s.r., and magnetic moment measurements.

Cited by 8 publications

References 0 publications

Rate of oxidative modification of cytochrome c by hydrogen peroxide is modulated by Hofmeister anions

Rate of oxidative modification of cytochrome c by hydrogen peroxide is modulated by Hofmeister anions

New chemical and stereochemical applications of organoiron complexes

Resonance Raman Characterization of (Oxoferryl)tetraphenylporphyrin Formed during Photodisproportionation of (Fe(TPP))2O in a Detergent Micelle at Room Temperature

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Resonance Raman Characterization of (Oxoferryl)tetraphenylporphyrin Formed during Photodisproportionation of (Fe(TPP))₂O in a Detergent Micelle at Room Temperature