Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This communication presents four different assay systems for the determination of myeloperoxidase in body fluids. One is based on conventional chemiluminescence, two on luminescence-amplified enzyme measurement using either spiroadamantane-1,2-dioxetanes with alkaline phosphatase or luminol/peroxidase/4-iodophenol coupled with a peroxidase label. The assays covered the range 0-600 micrograms/l peroxidase. Established reference range for EDTA plasma from healthy volunteers gave an upper limit of 250 micrograms/l (95% confidence limits). Intra-assay coefficients of variation were less than 5% for all assays, as seen in compound precision profiles. Inter-assay variation was less than 10% throughout the whole concentration range. Kinetic curves for the light production were performed over a 2 hour period for the enhanced luminescence assays. Dynamic ranges of these assays were compared with the conventional colorimetric assay using 4-nitrophenyl phosphate--alkaline phosphatase. The assay was standardized using a commercially available myeloperoxidase preparation with defined enzymatic activity. The protein content was estimated and the laboratory standard compared and calibrated in mass units.
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PMID:A comparison of four immunometric assays for myeloperoxidase using luminescent and colorimetric signal detection. 217 39

This article briefly describes the use of a photon counting system (ARGUS-100) in the detection of low levels of light. The ARGUS-100 was used in determining ATP in cell sections from tumor tissues and in measuring a luminescence-enhanced immunoluminometric assay, using ferritin as the analyte, based on the luminol-peroxide-4-iodophenol reaction with peroxidase as the enzyme. The aim is not so much the presentation of data, but rather to show the potentials of the photon counting camera in increasing our knowledge of the cellular and subcellular levels, as well as lowering the detection limits in already sensitive systems, such as immunoassays.
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PMID:Low light level in vitro monitoring of cellular and antigen-antibody reactions using a photon detection camera system--new perspectives for clinical diagnosis and research. 240 95

The application of 4-iodophenol as a signal enhancer for luminol-based immunodot and Western blotting assays was investigated. Immunodetection of biotin-bovine serum albumin (BSA) using a rat anti-biotin antibody for immunodot binding and goat anti-biotin peroxidase conjugate for Western blotting assays was employed to demonstrate the signal enhancement attainable with 4-iodophenol. The addition of 4-iodophenol at a final working concentration of 52.2 microM to a light-emitting substrate, luminol, resulted in 3-fold and 10-fold signal enhancements for Western blotting and immunodot binding detection of biotin-BSA, respectively.
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PMID:Enhancement of luminol-based immunodot and Western blotting assays by iodophenol. 305 94

A competitive enhanced luminescent enzyme immunoassay for serum progesterone is described, which is based on a 11 alpha-hydroxyprogesterone 11-hemisuccinyl-horseradish peroxidase conjugate and a black polystyrene microtitre plate sensitised with anti-progesterone IgG. Bound label was determined using a mixture of 4-iodophenol, luminol and peroxide, and the light emitted from the wells of the plate quantitated using a luminescent plate reader. The assay was sensitive (detection limit 0.5 pg), precise (CV 2.7 - 9.0% in the concentration range 4.3-67.7 nM) and showed good correlation (r = 0.99) with a conventional radioimmunoassay.
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PMID:An enhanced chemiluminescence enzyme immunoassay for serum progesterone. 640 58

4-Substituted phenyl boronic acids (e.g., 4-iodo, 4-bromo, 4-phenyl) are effective enhancers of the horseradish peroxidase (Type VIA) catalysed chemiluminescent oxidation of various pyrido[3,4-d]pyridazine-1,4(2H,3H)dione derivatives. The most effective combination was 4-biphenylboronic acid and 8-amino-5-chloro-7-phenylpyrido[3,4-d]- pyridazine-1,4(2H,3H)dione. Generally, the intensity of light emission in the presence of peroxidase was higher with the pyridopyridazines than with sodium luminol. However, the blank light emission was much lower with sodium luminol than with the pyridopyridazines. A synergistic enhancement phenomenon was demonstrated for the combination of a 4-iodophenol and a 4-biphenylboronic acid enhancer with 8-amino-5-chloro-7-phenylpyrido[3,4-d]pyridazine-1,4(2H,3H) dione. The combination of these two enhancers produced a light emission intensity in an assay for 5 fmol of peroxidase that was 25% higher than expected from the sum of the individual light intensities.
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PMID:Effect of enhancers on the pyridopyridazine-peroxide-HRP reaction. 868 92

4-Iodophenylboronic acid has been synthesized and shown to be a potent enhancer of the chemiluminescent horseradish peroxidase (Type VI-A)-catalyzed oxidation of luminol and isoluminol. The enhancer was effective (>100-fold enhancement) in the concentration range 10-1500 microM. Light emission in the presence of the enhancer peaked at 5-10 min after initiation of the reaction and then decayed very slowly. 4-Iodophenylboronic acid also enhanced reactions catalyzed by horseradish peroxidase Type IX. The detection limit for Type VI-A horseradish peroxidase was 509 amol, and optimum signal enhancement was obtained at 769 microM compared to 154 microM for 4-iodophenol under the same conditions.
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PMID:Synthesis and characterization of 4-iodophenylboronic acid: a new enhancer for the horseradish peroxidase-catalyzed chemiluminescent oxidation of luminol. 881 87

The enhancers 1,1'-biphenyl-4-yl boronic acid and 4-iodophenol act synergistically in the horseradish peroxidase-catalysed oxidation of luminol. This concentration-dependent effect reduces background, increases signal and hence improves signal/background for detection of peroxidase. The same type of synergistic effect was found when 1,1'-biphenyl-4-yl boronic acid was added to a commercial enhanced chemiluminescence signal reagent (Amerlite Signal Reagent). This synergistic enhanced chemiluminescent endpoint (Amerlite Signal Reagent containing 1,1'-biphenyl-4-yl boronic acid) for a horseradish peroxidase label has been tested in the Amerlite TSH and the Amerlite TSH-30 Ultrasensitive assays. The detection limit (mean of 20 replicates of the zero standard+2SD) in the Amerlite TSH assay was 0.0029 mIU/L, and in the Amerlite TSH-30 Ultrasensitive assay the detection limit was 0.0005 mIU/L using the synergistic enhanced endpoint. Reassessment of the detection limit using a 1:40 dilution of the first standard (0.119 mIU/L) as the lowest assay standard gave a value of 0.0015 mIU/L for the Amerlite TSH-30 Ultrasensitive assay with the synergistic endpoint. A limited (n = 29) method comparison using samples from euthyroid, hyperthyroid and hypothyroid patients revealed excellent correlation between the conventional and synergistic TSH immunoassays.
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PMID:Super-sensitive enzyme immunoassay for thyroid stimulating hormone using a new synergistic enhanced chemiluminescent endpoint. 884 44

Hydroxypropyl methylcellulose, hydroxyethyl cellulose, and hydroxybutyl methylcellulose stabilized light emission in a boronic acid-enhanced chemiluminescent assay for horseradish peroxidase. The stabilization of light emission was concentration-dependent and more effective with substituted boronic acid enhancers (e.g. 4-iodophenylboronic acid) than with substituted phenol enhancers (e.g. 4-iodophenol). Hydroxybutyl methylcellulose improved the linearity of the dose-response curve in a peroxidase-based antioxidant assay and stabilized light emission post-consumption of the antioxidant (Trolox). This polymer had no effect on the signal from a peroxidase label immobilized on a membrane (dot blot) or on the inside surface of a microwell in an enzyme immunoassay for thyrotropin.
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PMID:Effect of polymers on enhanced chemiluminescent assays for peroxidase and peroxidase labels. 934 14

An ultrasensitive chemiluminescent enzyme immunoassay (CLEIA) was developed for the rapid detection and quantification of Lactobacillus brevis contaminants in beer and pitching yeast (Saccharomyces cerevisiae slurry collected for reinoculation). L. brevis cells trapped on a 47-mm nucleopore membrane (0.4-micron pore size) were reacted with a peroxidase-labelled Lactobacillus group E antibody and then subjected to an enhanced CLEIA analysis with 4-iodophenol as the enhancer. The combination of a nucleopore membrane with low background characteristics that enables the antigen-antibody reaction to proceed through the pores of the membrane and a labelled antibody prepared by the maleimide hinge method with minimal nonspecific binding characteristics was essential to minimize background in the detection of single cells. An ultrahigh sensitive charge-coupled device (CCD) camera equipped with a fiber optics image intensifier permitted the imaging of single cells. A clear correlation existed between the number of luminescent spots observed and the plate count [y (CLEIA) = 0.990x (plate count) + 15.9, where n = 7, r = 0.993, and P < 0.001]. Microscopic observation confirmed that the luminescent spots were produced by single cells. This assay could be used to detect approximately 20 L. brevis cells in 633 ml of beer within 4 h. Our ultrasensitive CLEIA could also be used to detect microcolonies approximately 20 microns in diameter which had formed on a membrane after 15 to 18 h of incubation. This method, which we called the microcolony immunoluminescence (MIL) method, increased the signal-to-noise ratio dramatically. The MIL method could be used to detect a 10(0) level of L. brevis contamination in 633 ml of beer and a 1/10(8) level of L. brevis contamination in pitching yeast within 1 day (15 to 18 h to form microcolonies and 2 h for CLEIA).
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PMID:Imaging of Lactobacillus brevis single cells and microcolonies without a microscope by an ultrasensitive chemiluminescent enzyme immunoassay with a photon-counting television camera. 936 39

The preparation of three new types of phenylboronic acid derivatives and their evaluation as enhancers on the luminol-H(2)O(2)-horseradish peroxidase (HRP) chemiluminescence (CL) reaction are described. After optimizing the CL reaction conditions, the CL system was applied to the HRP determination. Among the three phenylboronic acid derivatives, i.e. 4-(4, 5-diphenyl-1H-imidazol-2-yl)phenylboronic acid (DPA), 4-[4(or 5)-(4-dimethylaminophenyl)-5(or 4)-phenyl-1H-imidazol-2-yl]phenylboronic acid (DAPA) and 4-[4, 5-di(2-pyridyl)-1H-imidazol-2-yl]phenylboronic acid (DPPA), DPPA was found to be the most potent enhancer. The sensitivity obtained with DPPA was about 180 times higher than that without an enhancer. The detection limit of HRP obtained with DPPA was 0.15 ng/assay (ca. 3.5 fmol), which is comparable to that with 4-iodophenol under the conditions examined. All the phenylboronic acid derivatives examined had the effect of prolonging light emission compared to 4-iodophenol.
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PMID:New phenylboronic acid derivatives as enhancers of the luminol-H(2)O(2)-horseradish peroxidase chemiluminescence reaction. 1060 9


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