Formation of Phenoxy Radical by Binuclear Iron(III) Complex and Hydrogen Peroxide System

Abstract The crystal structures of two binuclear iron(III) complexes with linear μ-oxo bridge, Fe2OCl2 (tfpy)2 (ClO4)2 ·2CH3CN and Fe2OCl2(epy)2(ClO4)2 were determined, where (tfpy) and (epy) represent N,N-bis(2-pyridylmethyl)-tetrahydrofurfurylamine and N,N-bis(2-pyridylmethyl)-2-ethoxyethylamine, respectively. Their structural features are essentially the same as that of the corresponding linear binuclear complex with (tpa)-complex, Fe2OCl2(tpa)2(ClO4)2, where (tpa) is tris(2-pyridylmethyl)amine; the ligands (tfpy) and (epy) act as a tetradentate tripod-like ligand, and Fe-O (ethereal oxygen atom; these are located at the trans-position of bridging oxo-oxygen atom) distances are 2.209(4) and 2.264(2) Å for (tfpy) and (epy) compounds, respectively. These two (tfpy) and (epy) complexes exhibited much higher activity for the oxygenation of cyclohexane in the presence of hydrogen peroxide than that of the (tpa) complex. In contrast to this, the former two complexes exhibit negligible activity for the decomposition of hydrogen peroxide, whereas the catalase-like function of the (tpa) compound is remarkable. These are indicating that an active species for oxygenation of cyclohexane, which is assumed to be an iron(III)-hydroperoxide adduct with η1-coordination mode, should be different from that is operating for decomposition of hydrogen peroxide; for the latter case formation of a (μ-η1:η1-peroxo)diiron(III) species being stressed. The EHMO calculation showed that electronic interaction between the monodentate hydroperoxide adduct of the binuclear iron(IIl)-(tfpy) compound and the tetrahydrofuran ring of the ligand system may lead to facile peroxide-tetrahydrofuran linkage formation, and the interaction described above should promote the O-O cleavage of the peroxide ion heterolytically. Based on these discussions, it was concluded that heterolytic O-O bond cleavage of the iron(III)-hydroperoxide adduct caused by electronic interaction with organic moiety containing an ethereal-oxygen and by approach of the substrate which donates electron to the peroxide adduct should play an important role in producing a high-valent iron-oxo species in these systems. In the case of (tpa) complex, formation of a hydroperoxide adduct linking with the ligand system seems to be unfavorable because of both the steric and electronic reasons.

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Oxygenation of Nucleosides by Peroxide Adduct of Binuclear Iron(III) Complex with a μ-Oxo Bridge

Zeitschrift für Naturforschung C ◽

10.1515/znc-1999-7-815 ◽

1999 ◽

Vol 54 (7-8) ◽

pp. 554-561

Author(s):

Sayo Ito ◽

Yumiko Sasaki ◽

Yasuyuki Takahashi ◽

Shigeru Ohb ◽

Yuzo Nishida

Keyword(s):

Hydrogen Peroxide ◽

High Activity ◽

Structural Properties ◽

Coordination Mode ◽

Active Species ◽

Diacetic Acid ◽

Acid Hydroxylation ◽

Binuclear Iron ◽

Oxo Bridge

Abstract The (μ-oxo)(μ-carbonato)diiron(III) complex with H2(tfda) (H2(tfda) = 2-aminomethyl-tetrahydrofuran-N,N-diacetic acid) exhibited high activity for hydroxylation of 2′-deoxygua-nosine in the presence of hydrogen peroxide, giving 8-hydroxydeoxyguanosine, but its hy droxylation activity towards other nucleosides such as 2′-deoxyadenosine, adenosine or thym idine was found negligible. In the case of the Fe(III)-(ed a) complex (H2(eda) = 2-methoxyethylamine-N,N-diacetic acid), hydroxylation occurred mainly at the sugar site, converting 2′-deoxyguanosine to guanosine. Based on the spectroscopic and structural properties of these iron(III) compounds, it seems most likely that an intrinsic active species for hydroxylation should be an electrophilic peroxide adduct of the (μ-oxo)diiron(III) core with η1 coordination mode, while the contribution of OH· sides is ruled out.

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Synthesis and Characterization of a Binuclear Iron(III) Complex Bridged by 1-Aminocyclopropane-1-carboxylic Acid. Ethylene Production in the Presence of Hydrogen Peroxide

Inorganic Chemistry ◽

10.1021/ic9001626 ◽

2009 ◽

Vol 48 (9) ◽

pp. 3910-3912 ◽

Cited By ~ 9

Author(s):

Wadih Ghattas ◽

Zeinab Serhan ◽

Nadia El Bakkali-Taheri ◽

Marius Réglier ◽

Masahito Kodera ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Carboxylic Acid ◽

Ethylene Production ◽

Synthesis And Characterization ◽

Binuclear Iron

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Important Role of Tetrahydrofuran Ring in Activation of Hydrogen Peroxide in the Presence of Binuclear Iron(III) Complexes with Linearμ-Oxo Bridge

Chemistry Letters ◽

10.1246/cl.1995.885 ◽

1995 ◽

Vol 24 (10) ◽

pp. 885-886 ◽

Cited By ~ 10

Author(s):

Yuzo Nishida ◽

Takashi Okuno ◽

Sayo Ito ◽

Akihiko Harada ◽

Shigeru Ohba ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Binuclear Iron ◽

Activation Of Hydrogen Peroxide ◽

Oxo Bridge

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Preparation and Catalase-Like Function of a Binuclear Iron(III) Complex with N,N,N',N'-Tetrakis(2-pyridylmethyl)-2-hydroxy-1,3-diaminopropane

Zeitschrift für Naturforschung B ◽

10.1515/znb-1992-0121 ◽

1992 ◽

Vol 47 (1) ◽

pp. 115-120 ◽

Cited By ~ 10

Author(s):

Yuzo Nishida ◽

Miyuki Nasu ◽

Tetsuya Akamatsu

Keyword(s):

Hydrogen Peroxide ◽

Magnetic Properties ◽

Charge Transfer ◽

Room Temperature ◽

Analytical Data ◽

High Ability ◽

Conductivity Data ◽

Binuclear Species ◽

Binuclear Iron ◽

Perchlorate Salt

The complex derived from Fe(NO3)3 · 9H2O and perchlorate salt of N,N,N',N'-tetrakis- (2-pyridylmethyl)-2-hydroxy-1,3-diaminopropane (abbreviated as H(HPTP)) is formulated as a binuclear species with μ-alkoxo and μ-hydroxo bridges, [Fe2(HPTP)(OH)(NO3)2 ](ClO4)2, on the basis of analytical data, magnetic properties, and conductivity data. This complex reacts with hydrogen peroxide in water to form a violet adduct with new charge transfer bands in the range 520-600 nm. This adduct is very unstable at room temperature, indicating the high catalase-like function of this complex. The complex exhibits a high ability to degradate DNA in the presence of H2O2. The observed high catalase-like and bleomycin-like functions of the complex are discussed in terms of the activation of the peroxide ion by the binuclear iron(III) compound.

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Peroxidase Localization in Hartmanella Trophozoites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065778 ◽

1971 ◽

Vol 29 ◽

pp. 346-347 ◽

Cited By ~ 1

Author(s):

George E. Childs ◽

Joseph H. Miller

Keyword(s):

Hydrogen Peroxide ◽

Ultrastructural Localization ◽

Pathogenic Strain ◽

Oxidative Enzymes ◽

Differential Centrifugation ◽

Electron Microscopic ◽

Microscopic Studies ◽

The Subject ◽

Axenic Cultures

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.

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Fluorescent proteins for in vivo imaging, where's the biliverdin?

Biochemical Society Transactions ◽

10.1042/bst20200444 ◽

2020 ◽

Vol 48 (6) ◽

pp. 2657-2667

Author(s):

Felipe Montecinos-Franjola ◽

John Y. Lin ◽

Erik A. Rodriguez

Keyword(s):

Hydrogen Peroxide ◽

In Vivo Imaging ◽

Near Infrared ◽

Fluorescent Protein ◽

Fluorescent Proteins ◽

Fluorescent Imaging ◽

Infrared Light ◽

Red Fluorescent Protein ◽

Color Palette

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.

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Protective effect of chitooligosaccharides on hydrogen peroxide-induced PC-12 cells death by inhibition of oxidative damage

Cell Biology International ◽

10.1042/cbi034s027d ◽

2010 ◽

Vol 34 (8) ◽

pp. S27-S27

Author(s):

Xueling Dai ◽

Ping Chang ◽

Ke Xu ◽

Changjun Lin ◽

Hanchang Huang ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Oxidative Damage ◽

Protective Effect ◽

Pc 12 Cells ◽

Cells Death

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Signal-regulated oxidation of proteins via MICAL

Biochemical Society Transactions ◽

10.1042/bst20190866 ◽

2020 ◽

Vol 48 (2) ◽

pp. 613-620

Author(s):

Clara Ortegón Salas ◽

Katharina Schneider ◽

Christopher Horst Lillig ◽

Manuela Gellert

Keyword(s):

Signal Transduction ◽

Hydrogen Peroxide ◽

Cell Death ◽

Redox Regulation ◽

Signal Transduction Pathways ◽

Cellular Functions ◽

Intracellular Signals ◽

Amino Acid Side Chains ◽

Specific Receptors ◽

Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

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