-
Bioorganicheskaia Khimiia 2006Peroxidase oxidation of o-dianisidine, 3,3',5,5'-tetramethylbenzidine, and o-phenylenediamine in the presence of sodium dodecyl sulfate (SDS), an anionic surfactant, was...
Peroxidase oxidation of o-dianisidine, 3,3',5,5'-tetramethylbenzidine, and o-phenylenediamine in the presence of sodium dodecyl sulfate (SDS), an anionic surfactant, was spectrophotometrically studied. It was found that 0.1-100 mM SDS concentrations stabilize intermediates formed in the peroxidase oxidation of these substrates. The cause of the stabilization is an electrostatic interaction between positively charged intermediates and negatively charged surfactant.
Topics: Benzidines; Dianisidine; Horseradish Peroxidase; Oxidation-Reduction; Phenylenediamines; Sodium Dodecyl Sulfate; Spectrophotometry
PubMed: 16523724
DOI: No ID Found -
Clinical Biochemistry Dec 1974
Topics: Benzidines; Chlorine; Chlorpromazine; Colorimetry; Erythrocytes; Hemoglobins; Humans; Hydrogen Peroxide; Indicators and Reagents; Methods; Peroxidases; Plants; Water
PubMed: 4442222
DOI: 10.1016/s0009-9120(74)92784-2 -
Annals of the New York Academy of... 1982Superoxide anion radicals have been implicated recently as mediators of inflammation and tissue injury. Protection from superoxide anion radicals is provided primarily... (Review)
Review
Superoxide anion radicals have been implicated recently as mediators of inflammation and tissue injury. Protection from superoxide anion radicals is provided primarily by a copper-containing, intracellular enzyme (superoxide dismutase) (SOD) that catalyzes the dismutation of superoxide to hydrogen peroxide and oxygen. We have found that the action of cytoplasmic SOD to scavenge superoxide and thereby to inhibit superoxide-mediated reactions can be mimicked by the copper-containing plasma protein and acute-phase reactant, ceruloplasmin. Ceruloplasmin, at concentrations present in normal plasma, inhibited reduction of both cytochrome c and nitroblue tetrazolium (NBT) mediated by the aerobic action of xanthine oxidase on hypoxanthine (a superoxide-generating system). Ceruloplasmin neither inhibited formation of uric acid by xanthine oxidase nor accelerated autooxidation of cytochrome c. Furthermore, in an experimental system in which contact between ceruloplasmin and indicator was prevented by a relatively impermeable lipid membrane barrier, ceruloplasmin inhibited reduction of NBT trapped within liposomes exposed to xanthine oxidase and hypoxanthine. Ceruloplasmin also inhibited reduction of cytochrome c and NBT mediated by the aerobic action of xanthine oxidase on acetaldehyde (another superoxide-generating system) and mimicked the activity of purified human erythrocyte SOD by inhibiting photoreduction of NBT and by accelerating aerobic photooxidation of dianisidine. Ceruloplasmin could be separated from purified human erythrocyte SOD by electrophoresis on alkaline 12% polyacrylamide gels and identified by its superoxide-scavenging activity. These results suggest that ceruloplasmin may function as a circulating scavenger of oxygen-derived free radicals.
Topics: Acute Disease; Animals; Anti-Inflammatory Agents; Ceruloplasmin; Erythrocytes; Free Radicals; Humans; Inflammation; Neutrophils; Oxygen; Phagocytes; Superoxide Dismutase; Superoxides
PubMed: 6284006
DOI: 10.1111/j.1749-6632.1982.tb22150.x -
Polymers Dec 2020The pronouncedly low thermal conductivity of polymers in the range of 0.1-0.2 W m K is a limiting factor for their application as an insulating layer in microelectronics...
The pronouncedly low thermal conductivity of polymers in the range of 0.1-0.2 W m K is a limiting factor for their application as an insulating layer in microelectronics that exhibit continuously higher power-to-volume ratios. Two strategies can be applied to increase the thermal conductivity of polymers; that is, compounding with thermally conductive inorganic materials as well as blending with aromatic units arranged by the principle of π-π stacking. In this study, both strategies were investigated and compared on the example of epoxy-amine resins of bisphenol A diglycidyl ether (BADGE) and 1,2,7,8-diepoxyoctane (DEO), respectively. These two diepoxy compounds were cured with mixtures of the diamines isophorone diamine (IPDA) and -dianisidine (DAN). The epoxy-amine resins were cured without filler and with 5 wt.-% of SiO nanoparticles. Enhanced thermal conductivity in the range of 0.4 W·m·K was observed exclusively in DEO-based polymer networks that were cured with DAN (and do not contain SiO fillers). This observation is argued to originate from π-π stacking of the aromatic units of DAN enabled by the higher flexibility of the aliphatic carbon chain of DEO compared with that of BADGE. The enhanced thermal conductivity occurs only at temperatures above the glass-transition point and only if no inorganic fillers, which disrupt the π-π stacking of the aromatic groups, are present. In summary, it can be argued that the bisphenol-free epoxy-amine resin with an epoxy compound derivable from natural resources shows favorably higher thermal conductivity in comparison with the petrol-based bisphenol-based epoxy/amine resins.
PubMed: 33375238
DOI: 10.3390/polym13010065 -
Scandinavian Journal of Clinical and... 1962
Topics: Dianisidine; Glucose; Glucose Oxidase; Oxidoreductases; Peroxidases; Sensitivity and Specificity
PubMed: 13952612
DOI: 10.1080/00365516209051298 -
ChemPlusChem Jul 2023A mechanochemical method was used to obtain four new quercetin (QUE) co-crystals. Three co-formers have the systems of the heterocyclic rings with the oxygen and...
A mechanochemical method was used to obtain four new quercetin (QUE) co-crystals. Three co-formers have the systems of the heterocyclic rings with the oxygen and nitrogen atoms and they form co-crystals at the stoichiometric ratio of 1 : 2. In contrast, the QUE : o-dianisidine co-crystal represents the 1 : 1 stoichiometry and the former molecule is the aniline derivative. The X-ray crystallography and FT-IR and FT-Raman spectra revealed formation of the intermolecular O-H…N or N-H…O hydrogen bonds. The dynamics of the hydrogen bonds was investigated using the XPS method. The N 1s XPS spectra showed no proton transfer in the QUE : FEN and QUE : O-DIA co-crystal systems. The QUE : BZFP and QUE : EBZFP show the two-site static disorder across the proton transfer pathway to the pyridine ring, with the occupancies (C=N : C=NH ) of 72 : 28 and 77 : 23, respectively.
PubMed: 37337973
DOI: 10.1002/cplu.202300166 -
Analytical Biochemistry Apr 1962
Topics: Biphenyl Compounds; Dianisidine; Glucose; Glucose Oxidase; Oxidation-Reduction; Oxidoreductases; Sucrose
PubMed: 13869950
DOI: 10.1016/0003-2697(62)90119-7 -
Antonie Van Leeuwenhoek Mar 1989The detection of L-pyrrolidonyl peptidase activity is extremely useful for the differentiation of Enterococcus species and Streptococcus pyogenes from other members of... (Comparative Study)
Comparative Study
The detection of L-pyrrolidonyl peptidase activity is extremely useful for the differentiation of Enterococcus species and Streptococcus pyogenes from other members of the family Streptococaceae. This analysis has generally been performed utilizing the hydrolyzable substrate L-pyrrolidonyl beta-naphthylamine. After the substrate was hydrolyzed, free beta-naphthylamine has been detected utilizing the reagent para-dimethylaminocinnamaldehyde. The cinnamaldehyde and naphthylamine reagents combined to form an orange color, much like the indole reaction. The use of the cinnamaldehyde reagent had several drawbacks however: color development was not sharp, and the reagent was difficult to produce, and it was not stable. A new indicator system employing tetrazotized 0-dianisidine was developed. An extremely deep burgundy colored complex resulted from the reaction between the new indicator and B-Naphthylamine. This diazo reagent showed excellent correlation with results obtained with para-dimethylaminocinnamaldehyde and yielded more objective, distinct endpoints. This inexpensive reagent can be utilized either in a liquid form or dried on paper discs.
Topics: Aminopeptidases; Benzidines; Cinnamates; Dianisidine; Evaluation Studies as Topic; Humans; Pyroglutamyl-Peptidase I; Streptococcus; Streptococcus pyogenes
PubMed: 2569292
DOI: 10.1007/BF00393855 -
Bulletin of Experimental Biology and... May 2013We described a spectrophotometric method for measuring hemoglobin peroxidase activity in human plasma using o-dianisidine (o-DA) as the substrate and myeloperoxidase...
We described a spectrophotometric method for measuring hemoglobin peroxidase activity in human plasma using o-dianisidine (o-DA) as the substrate and myeloperoxidase specific inhibitor 4-aminobensoic acid hydrazide (ruling out the probable contribution of myeloperoxidase to the measured parameter value). The optimal conditions (pH 5.5; 2 mM H2O2) have been determined, at which hemoglobin makes the main contribution to plasma oxidation of o-DA. A significant positive correlation between hemoglobin peroxidase activity measured by the spectrophotometric method and hemoglobin level measured by the pyridine hemochromogenic method has been detected (r=0.624; p<0.01) in plasma specimens from 16 donors. Plasma hemoglobin peroxidase activities were measured in healthy individuals and patients with type 2 diabetes mellitus and coronary heart disease. High plasma hemoglobin peroxidase activities in both groups of patients indicates disorders in the mechanisms of clearance of hemoglobin and its highly reactive derivatives and can serve as specific markers of diseases associated with oxidative stress.
Topics: 4-Aminobenzoic Acid; Biomarkers; Coronary Disease; Diabetes Mellitus, Type 2; Dianisidine; Hemoglobins; Humans; Oxidative Stress; Peroxidase
PubMed: 23667888
DOI: 10.1007/s10517-013-2095-3 -
Methods in Molecular Biology (Clifton,... 2024Angiogenesis is the process of new blood vessel formation from preexisting vasculature. It is an integral component in normal embryonic development and tissue repair....
Angiogenesis is the process of new blood vessel formation from preexisting vasculature. It is an integral component in normal embryonic development and tissue repair. Dysregulation of angiogenesis might lead to tissue ischemia (resulting from reduced blood vessel formation) or major diseases such as cancer (abnormal vascular growth). This makes angiogenesis an excellent area of research for cancer therapeutics, and various animal models including zebrafish are used to study blood vessel development. As most of the techniques used to study angiogenesis are complex and cumbersome, in this chapter, we provide two simple assays to study angiogenesis with live and fixed zebrafish embryos/larvae.
Topics: Animals; Female; Angiogenesis; Zebrafish; Embryonic Development; Larva; Perciformes; Neoplasms
PubMed: 38285352
DOI: 10.1007/978-1-0716-3625-1_21