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)

Granulocytes from the peripheral blood of normal subjects and a patient with hereditary myeloperoxidase deficiency were homogenized in 0.34 M sucrose. A granule-rich fraction, prepared by sedimentation at 27,000 x g for 20 min, contained components that killed C. parapsilosis in vitro. These were extractable with 0.01 M citric acid and were shown by micropreparative polyacrylamide electrophoresis to be multiple. The candidacidal activity of these neutrophil components was heat stable and they were somewhat more active at pH 5.0 than at pH 7.0. When rabbit or guinea pig heterophils were obtained from sterile peritoneal exudates and similarly fractionated, they also were found to contain components that killed C. parapsilosis in vitro. These were primarily associated with a group of lysosomal cationic proteins lacking direct counterpart in human neutrophils. Among the candidacidal components of the human neutrophil was a protein, more cationic than lysozyme, that exhibited naphthol-ASD acetate esterase activity.
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PMID:Nonoxidative fungicidal mechanisms of mammalian granulocytes: demonstration of components with candidacidal activity in human, rabbit, and guinea pig leukocytes. 4 98

Reactions using diaminobenzidine (DAB) to localize the enzyme peroxidase in neutrophils and peroxidase-antiperoxidase (PAP) complex during immunological staining are usually performed in Tris-HCl or phosphate buffer at pH 7.2-7.6. However, DAB solutions at pH 7.2-7.6 often demonstrate erythrocyte pseudoperoxidase as well. By lowering the pH of the DAB solutions, it is possible to selectively suppress the reactivity of pseudoperoxidase while maintaining optimal reactions in neutrophils and PAP complex. For this purpose we recommend ammonium acetate-citric acid buffer at pH 5.5 (pH 5.0-6.0) containing 44 mg DAB per 100 ml buffer and 0.003%-0.03% with respect to H2O2.
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PMID:A comparison of methods using diaminobenzidine (DAB) to localize peroxidases in erythrocytes, neutrophils, and peroxidase-antiperoxidase complex. 8 20

We tested the ability of human peripheral blood monocytes to kill Candida albicans and Candida parapsilosis. Evidence that multiple fungicidal mechanisms operate in normla monocytes was found. Normal monocytes ingested and killed viable C. albicans, and could iodinate heat-killed C. albicans. Both functions were defective in monocytes from subjects with myeloperoxidase deficiency or chronic granulomatous disease. Methimazole, isoniazid, and aminotriazole inhibited iodination by normal monocytes without impairing their ability to kill C. albicans, indicating that iodination was not essential to the myeloperoxidase-hydrogen peroxide-mediated fungicidal system of the monocyte. C. parapsilosis, an organism killed with supranormal efficacy by monocytes from a patient with hereditary myeloperoxidase deficiency, was selected to examine the myeloperoxidase-independent fungicidal mechanisms of monocytes. Monocytes were obtained from the blood of normal or leukemic subjects and homogenized in 0.34 M sucrose to yield fractions rich in cytoplasmic granules. These fractions were extracted with 0.01 M citric acid and the soluble components were separated by micropreparative polyacrylamide electrophoresis. Monocytes were found to contain cationic proteins, other than myeloperoxidase, that kill C. parapsilosis in vitro.
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PMID:The fungicidal mechanisms of human monocytes. I. Evidence for myeloperoxidase-linked and myeloperoxidase-independent candidacidal mechanisms. 12 29

The presence of acid phosphatase, beta-glucuronidase and aryl sulfatase in juxtaglomerular cell granules (JGG) as well as the uptake and concentration of certain low molecular weight dyes by these granules have repeatedly suggested that they are akin to lysosomes. In the present experiments, rats were injected with three substances of widely different molecular weight and physicochemical properties--sucrose, iron sorbitol-citric acid complex (Jectofer) and horseradish peroxidase--that are well known to selectively concentrate in renal tubular cell lysosomes. None of these substances was found to enter the JGG to any significant degree, although both sucrose and Jectofer were evident in juxtaglomerular cells. Contrary to previous reports, thorium dioxide (Thorotrast) particles were not detected in the JGG after parenteral injection. These results indicate that JGG do not possess any significant lysosomal function and raise the question of the role of hydrolytic enzymes in the physiology of these granules.
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PMID:On the lysosomal function of juxtaglomerular granules. 61 Jul 7

We assessed the analytical performance of the co-immobilized hexokinase (EC 2.7.1.1) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) method for D-glucose analysis on the Technicon SMAC. The enzyme-containing coils were usable for one month, or 12 000 tests. Bilirubin, hemoglobin, lipemia, creatinine, uric acid, citric acid, and ascorbic acid did not interfere. Results with this method were compared to those by the National Glucose Reference Method. The upper limits of the total error estimate (a combination of random and systematic errors) were 76, 74, and 125 mg/liter at concentrations of 500, 1200, and 3000 mg/liter, respectively. The error estimates were less than allowable errors based on medical usefulness; thus the method was judged to perform acceptably with respect to the Reference Method. We also present performance data for the routine SMAC glucose oxidase (EC 1.1.3.4)/Peroxidase (EC 1.11.1.7) 3-methyl-2-benzothianolinone hydrazone-N,N-dimethylaniline method, the direct hexokinase method with the Du Pont aca, and the glucose oxidase oxygen-rate method with the Beckman Glucose Analyzer.
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PMID:Evaluation of the co-immobilized hexokinase/glucose-6-phosphate dehydrogenase method for glucose, as adapted to the Technicon SMAC. 65 1

Changes are known to occur in the salivary composition of asthmatic patients treated with beta 2-adrenoceptor agonists. To evaluate the precise contribution of the agonist to the impaired saliva secretion, 15 asthmatic patients, 15-23 yr old, were given two dose levels of agonist, either terbutaline or salbutamol. The lower dose, 0.15-3.0 mg/day, represented the therapeutic level used by the patients. During a wash-out period of one month, the asthma was treated with budesonide, a corticosteroid spray. Then a daily dose of 32 mg of terbutaline or salbutamol was given for one month. Samples of whole saliva, stimulated by chewing, and parotid saliva, stimulated by citric acid, were collected on three occasions: (1) at the end of the low-dose agonist treatment; (2) at the end of the wash-out period; and (3) at the end of the high-dose agonist treatment. During the high dosing the secretion rate of parotid saliva decreased and the concentrations of its total protein, amylase, hexosamine and the ratio of hexosamine/total protein were lowered. The output per minute of total protein, amylase, hexosamine, peroxidase, lysozyme, secretory IgA and potassium decreased. There were only small differences in secretion rates or saliva composition between samples collected at the end of the low-dose and at the end of the wash-out period. Thus, treatment with beta 2-adrenoceptor agonists impairs saliva secretion in asthmatics.
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PMID:Saliva composition in asthmatic patients after treatment with two dose levels of a beta 2-adrenoceptor agonist. 170 74

A pH table is reported for citric acid-ammonium acetate buffers that are useful for horseradish peroxidase (HRP) histochemistry.
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PMID:Citric acid-ammonium acetate buffer. 188 93

We have developed enzymoimmunoassays (EIA) for the quantitation of antibodies (Ab) to tetanus and diphtheria toxoids (TT, DT) using Immulon I plates coated with the appropriate toxoid. A preparation of human tetanus immunoglobulin with a known concentration of anti-TT Ab was used as calibrator of the anti-TT antibody assay. The assay of anti-DT Ab is calibrated with a pool of human sera whose anti-DT Ab concentration was determined by quantitative immunoelectrophoresis, using a horse anti-DT with known Ab concentration as calibrator. A peroxidase-conjugated anti-human IgG was used in both assays. ABTS was used as substrate, and the reaction was stopped after 1 min incubation with citric acid and the OD measured at 414 nm on a Vmax reader. The assays have been applied to a variety of clinical situations. In patients suspected of having tetanus, the quantitation of antibodies has been helpful in establishing a diagnosis. In patients with a history of hypersensitivity to tetanus toxoid, verification of the levels of anti-TT antibody may prevent unnecessary and potentially harmful immunizations. The assays have also been used for the diagnostic evaluation of the humoral immune response to TT and DT, both in pediatric patients and in immunosuppressed patients. Several non-responders have been detected, and we have recently used the assay to monitor the effects of fish oil administration on the humoral immune response.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quantitation of anti-tetanus and anti-diphtheria antibodies by enzymoimmunoassay: methodology and applications. 199 62

The concentrations of o-phenylenediamine (OPD), H2O2, citrate and H+ in a substrate buffer for peroxidase immunoassays were optimized for minimal background. The background was reduced 2-3 fold with 5.5 mM OPD, 3 mM H2O2, 150 mM citric acid/sodium citrate, pH 4.8, and the reproducibility interassay was increased. A further 3-5 fold reduction of the background was obtained by the addition of 1.5 mM acetanilide, 0.14 mM beta-mercaptoethanol and 5 mM nitrilotriacetic acid to the substrate buffer. This low-background substrate buffer allows increased sensitivity and lowers the interassay variation coefficient. It has been used successfully in peroxidase immunoassays of human C-reactive protein, human antiestreptolysin and human rheumatoid factor.
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PMID:Addition of reducing agents to the peroxidase-o-phenylenediamine buffer reduces background of enzyme immunoassays. 254 22

Biotin is a cofactor for carboxylases used in fatty acid synthesis, gluconeogenesis, and energy production by the citric acid cycle. Although lung has low levels of this vitamin overall, high concentrations were demonstrated histochemically in Clara cells of mouse, rat, hamster, and guinea pig using avidin conjugated to peroxidase. Lesser concentrations were found in type II cells of mouse, rat, and hamster but not guinea pig. By electron microscopy, biotin stores in mouse Clara cells were localized to mitochondria, while those in type II cells were present in both mitochondria and the cytoplasmic matrix. Biotin stores in type II cells are probably used mainly in fatty acid synthesis but also in gluconeogenesis and energy production. The reason for particularly high concentrations in the mitochondria of Clara cells is unknown.
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PMID:Biotin stores in rodent lungs: localization to Clara and type II alveolar cells. 320 17


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