Studies on the chlorinating activity of myeloperoxidase.

Harrison, John; Schultz, Julius

doi:10.1016/s0021-9258(17)33749-3

Cited by 862 publications

(158 citation statements)

References 9 publications

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“…It belongs to mammalian peroxidase superfamily whose other members are myeloperoxidase (MPO), eosinophil peroxidase (EPO), and thyroid peroxidase (TPO). Lactoperoxidase, MPO, and EPO play important roles in strengthening the innate immune system by catalyzing the conversion of halide or thiocyanate ions into potent ions that are toxic to pathogens (1)(2)(3)(4). These peroxidases are widely present in mammalian systems.…”

Section: Introductionmentioning

confidence: 99%

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Inhibition of Lactoperoxidase by Its Own Catalytic Product: Crystal Structure of the Hypothiocyanate-Inhibited Bovine Lactoperoxidase at 2.3-Å Resolution

Singh

Sharma

et al. 2009

Biophysical Journal

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To the best of our knowledge, this is the first report on the structure of product-inhibited mammalian peroxidase. Lactoperoxidase is a heme containing an enzyme that catalyzes the inactivation of a wide range of microorganisms. In the presence of hydrogen peroxide, it preferentially converts thiocyanate ion into a toxic hypothiocyanate ion. Samples of bovine lactoperoxidase containing thiocyanate (SCN(-)) and hypothiocyanate (OSCN(-)) ions were purified and crystallized. The structure was determined at 2.3-A resolution and refined to R(cryst) and R(free) factors of 0.184 and 0.221, respectively. The determination of structure revealed the presence of an OSCN(-) ion at the distal heme cavity. The presence of OSCN(-) ions in crystal samples was also confirmed by chemical and spectroscopic analysis. The OSCN(-) ion interacts with the heme iron, Gln-105 N(epsilon1), His-109 N(epsilon2), and a water molecule W96. The sulfur atom of the OSCN(-) ion forms a hypervalent bond with a nitrogen atom of the pyrrole ring D of the heme moiety at an S-N distance of 2.8 A. The heme group is covalently bound to the protein through two ester linkages involving carboxylic groups of Glu-258 and Asp-108 and the modified methyl groups of pyrrole rings A and C, respectively. The heme moiety is significantly distorted from planarity, whereas pyrrole rings A, B, C, and D are essentially planar. The iron atom is displaced by approximately 0.2 A from the plane of the heme group toward the proximal site. The substrate channel resembles a long tunnel whose inner walls contain predominantly aromatic residues such as Phe-113, Phe-239, Phe-254, Phe-380, Phe-381, Phe-422, and Pro-424. A phosphorylated Ser-198 was evident at the surface, in the proximity of the calcium-binding channel.

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Section: Introductionmentioning

confidence: 99%

“…These peroxidases are widely present in mammalian systems. Myeloperoxidase is found in granules of circulating polymorphonuclear neutrophils and monocytes (2,3). Eosinophil peroxidase is an important granule protein of eosinophils (4), whereas LPO is present in exocrine secretions.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Lactoperoxidase by Its Own Catalytic Product: Crystal Structure of the Hypothiocyanate-Inhibited Bovine Lactoperoxidase at 2.3-Å Resolution

Singh

Sharma

et al. 2009

Biophysical Journal

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“…Such a mechanism also could serve to minimize self-inactivation of MPO that would be expected from production and release of free HOCl. Previous studies have provided strong evidence that MPO can produce diffusible and volatile products of chloride oxidation, presumably HOCl and/or Cl 2 (26), but determination of the relative fluxes through these two pathways and the factors that determine the efficacies of these pathways remain to be determined, and the relative flux rates are likely to vary with types and concentrations of substrates present.…”

Section: Discussionmentioning

confidence: 99%

Selective oxidation in vitro by myeloperoxidase of the N-terminal amine in apolipoprotein B-100

Yang

Wang

Krutchinsky

et al. 2001

Journal of Lipid Research

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In contrast to the multiple low abundance 2,4dinitrophenylhydrazine-reactive tryptic peptides formed by oxidation of LDL with reagent HOCl in vitro, myeloperoxidase-catalyzed oxidation produces a dominant product in considerably greater yield and selectivity. This modified peptide had a single amino-terminal sequence corresponding to amino acids 53-66 of apolipoprotein B-100 (apoB-100), but its mass spectra indicated a significantly higher mass than could be reconciled with simple modifications of this peptide. Subsequent studies indicate that this product appears to result from N-chlorination of the N-terminal amino group of apoB-100 and dehydrohalogenation to the corresponding imine, which may form the hydrazone derivative directly, or after hydrolysis to the ketone. The methionine residue is oxidized to the corresponding sulfoxide, and the primary sequence peptide (residues 1-14 of apoB-100) is linked by the intramolecular disulfide bond between C-12 and C-61 to the peptide composed of residues 53-66, as we have observed previously (

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“…[ 1,2 ] ClO − plays an essential role in various physiological and pathological processes, including preventing infection and destroying pathogens. [ 3–5 ] Therefore, abnormal ClO − concentration levels can lead to oxidative stress, tissue lesion, and many relative risks related to immune deficiency, myocardial injury, nerve damage, kidney disease, cardiovascular disease, and tumours. [ 6–11 ] Therefore, designing and developing efficient, as well as convenient, monitoring methods that can detect ClO − is significant.…”

Section: Introductionmentioning

confidence: 99%

Benzimidazole‐based turn‐on fluorescence probe developed for highly specific and ultrasensitive detection of hypochlorite ions in living cells

2021

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Hypochlorite (ClO−), as one of the active oxygen species (ROS), plays an essential role in the cellular defence system and organism immunity. In this paper, we successfully synthesized a new ‘turn‐on’ fluorescent probe BMF based on benzimidazole and characterized it by spectroscopic methods. The designed probe can quickly respond to ClO− with the obvious colour change from pink to colourless. Notably, the probe BMF exhibited almost no fluorescence, but showed strong fluorescence after adding ClO−, including an excellent fluorescence turn‐on effect. The fluorescence turn‐on phenomenon of BMF was attributed to the strong oxidation of ClO−, which severed the connecting double bond and disrupted the intramolecular charge transfer (ICT) system, plus light‐induced electron transfer effect between the fluorophore and the recognition group was discontinued. In addition, the cytotoxicity assay showed that the probe had lower cytotoxicity. Based on these advantages, we demonstrated that probe BMF might be a good candidate for detecting ClO− in biological systems.

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Studies on the chlorinating activity of myeloperoxidase.

Cited by 862 publications

References 9 publications

Inhibition of Lactoperoxidase by Its Own Catalytic Product: Crystal Structure of the Hypothiocyanate-Inhibited Bovine Lactoperoxidase at 2.3-Å Resolution

Inhibition of Lactoperoxidase by Its Own Catalytic Product: Crystal Structure of the Hypothiocyanate-Inhibited Bovine Lactoperoxidase at 2.3-Å Resolution

Selective oxidation in vitro by myeloperoxidase of the N-terminal amine in apolipoprotein B-100

Benzimidazole‐based turn‐on fluorescence probe developed for highly specific and ultrasensitive detection of hypochlorite ions in living cells

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