Hydrogen peroxide assay by using enhanced chemiluminescence of the luminol-H2O2-horseradish peroxidase system: Comparative studies

Dı́az, A. Navas; Sánchez, Francisco; García, J.A. González

doi:10.1016/0003-2670(96)00077-3

Cited by 60 publications

(29 citation statements)

References 15 publications

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“…Moreover, a large portion of this region also may serve as a membrane-targeting signal sequence that is proteolytically cleaved during cellular processing (19). Overall, the structure is held together by a buried disulfide bridge connecting the β 2 -β 3 loop with the β 8 -strand which is flanked by 68 Trp, a residue conserved among all β-subunit isoforms. On the other side, it packs against 114 Ile and 133 Val, both of which correspond to the similar Ile, Val, or Leu residues in other β-subunits (Fig.…”

Section: Significancementioning

confidence: 99%

Crystallographic insights into sodium-channel modulation by the β4 subunit

Gilchrist

Das

Petegem

et al. 2013

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

110

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Voltage-gated sodium (Na v ) channels are embedded in a multicomponent membrane signaling complex that plays a crucial role in cellular excitability. Although the mechanism remains unclear, β-subunits modify Na v channel function and cause debilitating disorders when mutated. While investigating whether β-subunits also influence ligand interactions, we found that β4 dramatically alters toxin binding to Na v 1.2. To explore these observations further, we solved the crystal structure of the extracellular β4 domain and identified 58 Cys as an exposed residue that, when mutated, eliminates the influence of β4 on toxin pharmacology. Moreover, our results suggest the presence of a docking site that is maintained by a cysteine bridge buried within the hydrophobic core of β4. Disrupting this bridge by introducing a β1 mutation implicated in epilepsy repositions the 58 Cys-containing loop and disrupts β4 modulation of Na v 1.2. Overall, the principles emerging from this work (i) help explain tissuedependent variations in Na v channel pharmacology; (ii) enable the mechanistic interpretation of β-subunit-related disorders; and (iii) provide insights in designing molecules capable of correcting aberrant β-subunit behavior.voltage-gated sodium channel | beta4 subunit | ProTx-II | X-ray structure | disease mutations

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Section: Significancementioning

confidence: 99%

Crystallographic insights into sodium-channel modulation by the β4 subunit

Gilchrist

Das

Petegem

et al. 2013

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

110

View full text Add to dashboard Cite

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“…The membranes were incubated with horseradish peroxidase-linked secondary antibody (1:4,000) in blocking buffer for 1 h at room temperature and washed with buffer for 30 min, replacing the buffer every 10 min. The immunoreactive proteins were detected using coumaric acid and luminol reagents (34).…”

Section: Methodsmentioning

confidence: 99%

Pulmonary Surfactant Phosphatidylglycerol Inhibits Mycoplasma pneumoniae-stimulated Eicosanoid Production from Human and Mouse Macrophages

Kandasamy¹,

Zarini

Chan³

et al. 2011

Journal of Biological Chemistry

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Mycoplasma pneumoniae is a human pathogen causing respiratory infections that are also associated with serious exacerbations of chronic lung diseases. Membranes and lipoproteins from M. pneumoniae induced a 4-fold increase in arachidonic acid (AA) release from RAW264.7 and a 2-fold increase in AA release from primary human alveolar macrophages. The bacterial lipoprotein mimic and TLR2/1 agonist Pam3Cys and the TLR2/6 agonist MALP-2 produced effects similar to those elicited by M. pneumoniae in macrophages by inducing the phosphorylation of p38 MAPK and p44/42 ERK1/2 MAP kinases and cyclooxygenase-2 (COX-2) expression. M. pneumoniae induced the generation of prostaglandins PGD 2 and PGE 2 from RAW264.7 cells and thromboxane B 2 (TXB 2 ) from human alveolar macrophages. Anti-TLR2 antibody completely abolished M. pneumoniae-induced AA release and TNF␣ secretion from RAW264.7 cells and human alveolar macrophages. Disruption of the phosphorylation of p44/ 42 ERK1/2 or inactivation of cytosolic phospholipase A 2 ␣ (cPLA 2 ␣) completely inhibited M. pneumoniae-induced AA release from macrophages. The minor pulmonary surfactant phospholipid, palmitoyl-oleoyl-phosphatidylglycerol (POPG), antagonized the proinflammatory actions of M. pneumoniae, Pam3Cys, and MALP-2 by reducing the production of AA metabolites from macrophages. The effect of POPG was specific, insofar as saturated PG, and saturated and unsaturated phosphatidylcholines did not have significant effect on M. pneumoniae-induced AA release. Collectively, these data demonstrate that M. pneumoniae stimulates the production of eicosanoids from macrophages through TLR2, and POPG suppresses this pathogen-induced response.

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“…[1][2][3][4] Therefore the determination of hydrogen peroxide is important in characterization and selection of honey samples for use as an antimicrobial agent. Several analytical methods have been proposed for the determination of H2O2, including spectrophotometry, [5][6][7][8] spectrofluorometry, 9-13 chemiluminescence [14][15][16][17] and electrochemical techniques. [18][19][20][21] Most of these methods are enzymatic methods that are of interest because of their high sensitivity and selectivity.…”

mentioning

confidence: 99%

Application of Crude Extract of Kohlrabi (Brassica oleracea gongylodes) as a Rich Source of Peroxidase in the Spectrofluorometric Determination of Hydrogen Peroxide in Honey Samples

2006

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Crude extract of kohlrabi (Brassica oleracea gongylodes) was prepared by a simple procedure and its enzymatic activity and total protein concentration were determined. It was found that this crude extract is a rich source of peroxidase (POx) and has high specific activity. Cross-linked polyvinylpyrrolidone was used as a stabilizer in the preparation of the crude extract. The POx activity of kohlrabi crude extract did not vary for at least 2 months when deoxygenated and stored at 4˚C. This extract was applied for the spectrofluorometric determination of hydrogen peroxide using homovanillic acid as a fluorogenic substrate. POx catalyzes the hydrogen peroxide oxidation of homovanillic acid to produce a dimer which shows strong fluorescence at 420 nm with excitation at 312 nm. In the optimum conditions, the calibration graph for hydrogen peroxide was linear up to 190 ng mL -1 , with a detection limit of 4.4 ng mL -1 . The relative standard deviation (RSD) was 1.48% for 50 ng mL -1 hydrogen peroxide. The proposed method was successfully applied to the determination of hydrogen peroxide in honey. The concentration-time profile of H2O2 produced upon dilution of honey was studied and H2O2 contents of some different honeys from various areas of Iran were determined.

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Hydrogen peroxide assay by using enhanced chemiluminescence of the luminol-H2O2-horseradish peroxidase system: Comparative studies

Cited by 60 publications

References 15 publications

Crystallographic insights into sodium-channel modulation by the β4 subunit

Crystallographic insights into sodium-channel modulation by the β4 subunit

Pulmonary Surfactant Phosphatidylglycerol Inhibits Mycoplasma pneumoniae-stimulated Eicosanoid Production from Human and Mouse Macrophages

Application of Crude Extract of Kohlrabi (Brassica oleracea gongylodes) as a Rich Source of Peroxidase in the Spectrofluorometric Determination of Hydrogen Peroxide in Honey Samples

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