Monomeric ferric heme peptide derivatives: Model systems for hemoproteins

Carraway, Angela D.; Povlock, Sue L; Houston, Melinda L; Johnston, David; Peterson, Jim

doi:10.1016/0162-0134(95)00026-7

Cited by 15 publications

(27 citation statements)

References 43 publications

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“…Because microperoxidases show a tendency to form aggregates in aqueous solutions (Harbury and Loach, 1959;Aaron et al, 1986;Adams, 1991;Carraway et al, 1995), dilute solutions of MP11 were allowed to equilibrate for at least 30 min prior to further experiments. This is important because the reactivity of MP11 monomers is markedly higher than that of dimers.…”

Section: Reaction Conditionsmentioning

confidence: 99%

Investigation of the Mechanism of Action of Microperoxidase-11, (MP11), a Potential Anti-cataract Agent, with Hydrogen Peroxide and Ascorbate

Spector

Zhou

et al. 2000

Experimental Eye Research

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Section: Reaction Conditionsmentioning

confidence: 99%

Investigation of the Mechanism of Action of Microperoxidase-11, (MP11), a Potential Anti-cataract Agent, with Hydrogen Peroxide and Ascorbate

Spector

Zhou

et al. 2000

Experimental Eye Research

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“…Therefore, in an aqueous medium, a water molecule occupies the sixth coordination position of the resting form of Fe(III)MP-11. MP-11 and the other MPs exhibit peroxidase activity because water is easily displaced from the heme iron sixth coordination position by a peroxide molecule ( Figure 1 ) [ 5 , 6 , 7 , 8 ]. The catalytic mechanism of microperoxidases is similar to that of the heme peroxidases, such as horseradish peroxidase.…”

Section: Introductionmentioning

confidence: 99%

Structure and Catalysis of Fe(III) and Cu(II) Microperoxidase-11 Interacting with the Positively Charged Interfaces of Lipids

et al. 2017

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Numerous applications have been described for microperoxidases (MPs) such as in photoreceptors, sensing, drugs, and hydrogen evolution. The last application was obtained by replacing Fe(III), the native central metal, by cobalt ion and inspired part of the present study. Here, the Fe(III) of MP-11 was replaced by Cu(II) that is also a stable redox state in aerated medium, and the structure and activity of both MPs were modulated by the interaction with the positively charged interfaces of lipids. Comparative spectroscopic characterization of Fe(III) and Cu(II)MP-11 in the studied media demonstrated the presence of high and low spin species with axial distortion. The association of the Fe(III)MP-11 with CTAB and Cu(II)MP-11 with DODAB affected the colloidal stability of the surfactants that was recovered by heating. This result is consistent with hydrophobic interactions of MPs with DODAB vesicles and CTAB micelles. The hydrophobic interactions decreased the heme accessibility to substrates and the Fe(III) MP-11catalytic efficiency. Cu(II)MP-11 challenged by peroxides exhibited a cyclic Cu(II)/Cu(I) interconversion mechanism that is suggestive of a mimetic Cu/ZnSOD (superoxide dismutase) activity against peroxides. Hydrogen peroxide-activated Cu(II)MP-11 converted Amplex Red® to dihydroresofurin. This study opens more possibilities for technological applications of MPs.

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“…The product of the hydrolysis retains the heme group covalently attached to cysteine residues 14 and 17. [6][7][8] Four microperoxidase types were identified according to the sequence of native cytochrome c, from which these peptide fragments are derived: microperoxidase-6, (CAQCHT), -8, (CAQCHTVE), -9 (KCAQCHTVE) and -11 (VQKCAQCHTVE). Microperoxidases exist in the ferric resting states, retain histidine as a fifth heme iron ligand but not the methionine residue at the sixth coordination position which, in this case, at neutral pH, is occupied by a water molecule.…”

Section: Introductionmentioning

confidence: 99%

“…The absence of methionine 80 at the sixth coordination position of microperoxidases favors the peroxidase activity of the hemepeptide. [6][7][8] Scheme 1, below, shows the structure of microperoxidase-9.…”

Section: Introductionmentioning

confidence: 99%

Reaction route control by microperoxidase-9/CTAB micelle ratios

Prieto

Marcon

Prado

et al. 2006

Phys. Chem. Chem. Phys.

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Microperoxidases (MP) as water-soluble models attract interest to studying the reaction mechanism of peroxidases because these heme peptides are able to form the same enzyme intermediates during the reaction with peroxides. In this work we have demonstrated that the association of Fe(III)MP-9 and Fe(III)MP-11 with CTAB micelles (MP-9/CTAB and MP11/CTAB) provides a microenvironment with an alkaline interface and a hydrophobic core that exhibits peroxidase behavior. This microenvironment shifts positively the redox potential of microperoxidases by approximately 100 mV. tert-Butylhydroperoxide (t-BuOOH) when added to the medium, converted Fe(III)MP-9/CTAB to MP-9/CTAB Compound II, a high valence oxidized intermediate of the heme peptide. Subsequent addition of diphenylacetaldehyde (DPAA) to MP-9/CTAB Compound II regenerated the native form of the enzyme, Fe(III)MP-9/CTAB, what characterizes the occurrence of a peroxidase cycle. Fe(III)MP-9/CTAB regenerated during the peroxidase cycle reacted with residual DPAA in the medium to form Fe(II)MP-9/CTAB, which indicates that both Fe(III)MP-9/CTAB and its oxyferryl form can use aldehydes as reducing agents. According to the determined reduction potential, Fe(III)MP-9 and Fe(III)MP-9/CTAB should be able to oxidize DPAA (reduction potential -630 mV). The reaction of MP-9/CTAB with DPAA produced benzophenone as final product, detected by infrared spectroscopy and mass spectrometry. Interestingly, a significant difference was observed in the benzophenone yield according to the micelle/MP-9 molar ratio.

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Monomeric ferric heme peptide derivatives: Model systems for hemoproteins

Cited by 15 publications

References 43 publications

Investigation of the Mechanism of Action of Microperoxidase-11, (MP11), a Potential Anti-cataract Agent, with Hydrogen Peroxide and Ascorbate

Investigation of the Mechanism of Action of Microperoxidase-11, (MP11), a Potential Anti-cataract Agent, with Hydrogen Peroxide and Ascorbate

Structure and Catalysis of Fe(III) and Cu(II) Microperoxidase-11 Interacting with the Positively Charged Interfaces of Lipids

Reaction route control by microperoxidase-9/CTAB micelle ratios

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