Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Two different fixatives were applied to human gastric mucosa for the study of antigenic marker substances. The first consists of 96% ethanol and 1% acetic acid (EA method), the second of 4% formaldehyde, 0.5% picric acid and 0.25% glutaraldehyde (FPG method). Samples of resected gastric specimens were fixed, dehydrated and cleared in benzene and embedded in paraplast. The morphology of gastric tissue was well preserved by both methods and permitted the simultaneous application of classical staining procedures and the immunoenzyme peroxidase technique for the demonstration of antigenic substances. The following marker substances could be demonstrated: Pepsinogen I and II group, surface epithelial antigen, parietal cell antigen, chief cell antigen, antral mucous cell antigen, carcinoembryonic antigen, goblet cell antigen and common site antigen of leucocytes. Various factors responsible for nonspecific reactions, such as endogeneous peroxidase activity and protein interactions were studied. The latter were circumvented by the use of highly purified antibodies or immunoglobulin fractions. The EA method proved to be the method of choice for future routine application of combined classical histology and immunoenzyme histology in gastric and intestinal diseases.
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PMID:Immunohistochemical studies on human gastric mucosa. Procedures for routine demonstration of gastric proteins by immunoenzyme techniques. 15 Jan 10

Association of herpes simplex virus (HSV)-related antigens with chromosomes was demonstrated in human and mouse cells biochemically transformed by HSV that had been irradiated with ultraviolet light. This was accomplished by using peroxidase-anti-peroxidase immunological staining with rabbit antisera that had high neutralizing titers against both HSV-specific thymidine kinase activity and virus infectivity. Antisera-against HSV did not react with chromosomes of uninfected cells nor did normal sera react with any of the constitutents of biochemically transformed cells. Methanol/acetic acid treatment of biochemically transformed cells eliminated their nuclear staining for HSV-related antigens. In vitro binding of HSV-related antigens to chromosomes was demonstrated by incubating soluble antigens from high salt extracts of HSV-infected cells with methanol/acetic acid-fixed chromosomes of biochemically transformed or uninfected cells, followed by exposure to antiserum against HSV and peroxidase-anti-peroxidase staining. There was no staining when soluble extracts from uninfected cells were substituted for those from HSV-infected cells. The results show that cells biochemically transformed and lytically infected by HSV, respectively, contain antigens, which like the Epstein-Barr virus-associated nuclear antigen (EBNA), bind to chromosomes in vivo and in vitro.
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PMID:Binding to chromosomes of herpes simplex-related antigens in biochemically transformed cells. 21 Apr 57

Membrane vesicles can be obtained from epimastigote forms of Trypansoma cruzi by incubating cells with either cross-linking reagents or acid pH. Acetate, phtalate or citrate, at pH 4.0, but not at higher pH values, were able to induce plasma membrane vesiculation. Vesicles have been purified by sucrose density centrifugation and their membrane origin was demonstrated by the following criteria: (a) Vesicles are 5--10 times richer in protein-bound iodine when they are prepared from cells previously labeled with 131I by the lactoperoxidase catalyzed reaction. (b) Electron microscopy of vesiculating cells shows physical continuity between cell plasma membrane and vesicle membrane. (c) Antibodies prepared against purified vesicles are able to agglutinate epimastigote forms of T. cruzi with sera dilutions up to 1 : 256 to 1 : 512. (d) Freeze-fracture studies of the purified vesicles have shown images of faces P and E compatible with known images of the intact cell plasma membrane. Typical preparations of acetate vesicles present the following characteristics: total carbohydrate : protein=1.5--2.0; orcinol : protein-0.07 and absence of diphenylamine reaction. Vesicles contain 0.2--0.5% and 0.3--1.0% of the total homogenate protein and carbohydrate, respectively. The presence of 10 major protein bands and 30--50-fold enrichment of the four sugar-containing macromolecules present in epimastigote forms of T. cruzi have been demonstrated in these preparations.
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PMID:Plasma membrane vesicles isolated from epimastigote forms of Trypanosoma cruzi. 36 44

We have studied the fragmentation by pepsin in 1 M-acetic acid of the erythrocyte anion-transport protein in erythrocyte membranes. The location of the fragments obtained was determined by radioiodinating the protein with the use of lactoperoxidase, and identifying the labelled peptides obtained in peptide "maps" of thermolysin digests of the fragments. Three of the fragments were found to be related overlapping products, and shared a common C-terminus. The major site of pepsin cleavage leading to the C-termini of these fragments was shown to be close to the major site of extracellular cleavage of the protein by proteinases active at a neutral pH. Another two fragments were isolated and shown to be derived from the C-terminal portion of the protein. No well-defined large radioactive fragments of the protein were solubilized from the membrane by pepsin in 1 M-acetic acid, the bulk of the radioactivity attributable to the anion transport protein being recovered in very small fragments that could not be resolved by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Our results suggest that the polypeptide chain of the anion-transport protein emerges at the extracellular face of the membrane 8000-13000 daltons on the N-terminal side of the major site of extracellular cleavage of the protein by proteinases that are active at a neutral pH.
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PMID:The anion-transport protein of the human erythrocyte membrane. Studies on fragments produced by pepsin digestion. 39 52

The IgE receptor of human basophils was purified by using simple and repetitive affinity chromatography on human IgE-Sepharose. Basophils were partially purified from peripheral blood of patients with chronic myelogenous or basophilic leukemia. Cells were labeled with 125I by using the lactoperoxidase method and were solubilized with nonionic detergent. Elution of IgE-Sepharose with 0.5 N acetic acid, 1% NP-40 allowed recovery of active IgE receptor. Analysis of human IgE receptor by SDS polyacrylamide gel electrophoresis with 10% gels demonstrated one major radioactive peak with an apparent m.w. of 58,000 to 68,000, somewhat larger than rat IgE receptor. The purified human IgE receptor was active since approximately 10 to 42% of labeled receptor could specifically rebind to insolubilized human IgE. Rebinding was blocked by nanomolar concentrations of soluble human IgE or rat IgE but not by human or rat IgG, heat-inactivated human IgE, or heat-aggregated human IgG; thus it appears that rat IgE receptor. The relative abilities of active rat IgE and active human IgE to inhibit human IgE receptor rebinding could not be precisely determined because of the limitations in assessing the proportion of human IgE that retains receptor-binding activity.
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PMID:Characterization of the IgE receptor isolated from human basophils. 48 84

The oxygen-consuming oxidation of indole-3-acetic acid (IAA) occurred much faster in the presence of horseradish peroxidase C (neutral isoenzyme) than in the presence of horseradish peroxidase A (acidic isoenzyme). An intermediate oxidation product of IAA was found to be a hydroperoxide species that reacted with the ferric enzymes to form Compound I at second order rate constants of 6.8 X 10(3) M-1--S-1 for peroxidase A and 2.0 X 10(6) M-1--S-1 for peroxidase C at pH 4.4 The hydroperoxide concentration reached about one-half of the initial IAA concentration at the end of the oxygen-consuming reaction and then decreased slowly. The main intermediate of the enzyme observed during the oxygen-consuming reaction was Compound II, which oxidized IAA to its free radical at rate constants of 1.5 X 10(3) M-1--S1 for peroxidase A and 1.2 times 10(4) M-1--S-1 for peroxidase C at pH 4.4 The results supported the mechanism that the oxygen consumption occurs mainly through the reaction of oxygen with the IAA free radical formed from the peroxidatic oxidation of IAA. The ferric enzymes were not reduced by IAA under strict anaerobic conditions in the presence of carbon monoxide but were reduced upon addition to a small amount of oxygen or hydrogen peroxide to the systems. The results suggested that the ferric enzyme is reduced by the IAA free radical but not by IAA itself. From a comparison of reactivities of oxyperoxidase and Compound II we concluded that the catalytic cycle of ferrous and oxyperoxidases is not involved in the IAA oxidase reaction.
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PMID:The mechanism of indole-3-acetic acid oxidation by horseradish peroxidases. 76 98

The kinetics of horseradish peroxidase catalyzed of scopoletin oxidation were observed to be sigmoidal. The apparent KmS for scopoletin is 0.9 mM. Inhibition of scopoletin oxidation by indole-3-acetic acid (IAA) appears to be non competitive. Non competitive inhibition by IAA suggests a more significant role of the peroxidase protein matrix in regulating the activity of the heme moiety.
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PMID:Effect of indole-3-acetic acid on the kinetics of horseradish peroxidase catalyzed scopoletin oxidation. 92 4

Guinea pig eosinophil granules contain a protein, the major basic protein (MBP), which accounts for more than half of the total granule protein, has a high content of arginine, and displays a remarkable tendency to form disulfide-linked aggregates. In this study we have purified a similar protein from human eosinophil granules and have compared the human MBP to the protein comprising the Charcot-Leyden crystal (CLC). Eosinophils from patients with various diseases were purified and disrupted, and the granule fraction was obtained. Examination of the granule fraction by transmission electron microscopy showed numerous typical eosinophil granules. Analyses of granule lysates by gel filtration and by polyacrylamide gel electrophoresis revealed the presence of peroxidase and MBP with properties similar to that previously found in guinea pig eosinophil granules. The human MBP had a molecular weight of 9,200, contained less than 1% carbohydrate, was rich in arginine, and readily formed disulfide-bonded aggregates. CLC were prepared from eosinophil-rich cell suspensions by homogenization in hypotonic saline. The supernates following centrifugation of cell debris spontaneously formed CLC. Analysis of CLC revealed the presence of a protein with a molecular weight of 13,000 containing 1.2% carbohydrate. The protein displayed a remarkable tendency to aggregate even in the presence of 0.2 M acetic acid. Human MBP and CLC protein differed in their molecular weights, carbohydrate compositions, and amino acid analyses. Mixtures of the MBP and the CLC protein yielded two bands in polyacrylamide gel electrophoresis. Neither eosinophil protein increased vascular permeability in the guinea pig skin or contracted the guinea pig ileum. The results indicate that the human MBP and the CLC are distinct substances with properties such that one cannot be derived from the other.
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PMID:Comparative properties of the Charcot-Leyden crystal protein and the major basic protein from human eosinophils. 94 77

An automatic micromethod is described for the estimation of plasma uric acid. The hydrogen peroxide formed when uric acid is oxidised by uricase, condenses by oxidation two molecules of p-hydroxyphenil-acetic acid in the presence of peroxidase. The product formed (dicarboxymethyl-5,5' dihydroxy-2,2' biphenyl) is fluorescent. This method permits one to estimate quantitites of uric acid of the order of 1 microng and permits measurement of uric acid in 50 microll of plasma. The values obtained for human plasma are compared to those supplied by a reductrimetric technique (SMA 12-60).
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PMID:[Automatic ultramicrotechnic for the determination of plasma uric acid]. 102 25

The optimal conditions for the extraction and isolation of immunoglobulins from the cell membrane (M-Ig) of T and B lymphocytes radioiodinated with lactoperoxidase were studied. A combination of 10M-urea, 1.5 M acetic acid and the non-ionic detergents Triton X-100 or Nonidet P-40 (NP-40) was found to overcome the tendency for membrane proteins to precipitate after extraction in urea-acetic acid alone. However, detection of T cell Ig was more dependent on detergent concentration than B cell M-Ig. Less T cell Ig was detected when the detergent concentration was increased from 0.1% to 1.0%, whereas the amount of B cell M-Ig was not affected by higher detergent concentrations.
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PMID:Factors influencing the isolation of membrane immunoglobulins from T and B lymphocytes. 1. Detergent effects and iodination conditions. 108 96


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