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)

Thyroid tissue obtained from 12 patients with Graves' disease and treated with thionamide drugs for 3-7 mo before subtotal thyroidectomy, from 12 patients with Graves' disease, similarly treated, and given 50 mug of triiodothyronine (T3) for 10 days before surgery, and from 12 euthyroid patients with solitary cold nodules was investigated to compare in vitro iodination of thyroglobulin in toxic diffuse goiter and in normal thyroid tissue. The supernates of the homogenates (105,000g) were subjected to sucrose density gradient centrifugation (5--28%) to separate the thyroglobulin fraction. The precipitates were treated with 1% digitonin and centrifuged to collect the supernate (particulate fraction). When thyroglobulin and particulate fractions obtained from the same patient were incubated with 125I-, iodide, glucose, and glucose oxidase, the amount of iodine bound to thyroglobulin was several times greater in toxic diffuse goiter than in normal thyroid tissue; administration of T3 did not affect iodination in toxic diffuse goiter. When the thyroglobulin fraction from each patient was incubated with a standardized quantity of peroxidase instead of the individual particulate fraction, the amount of iodine bound to thyroglobulin was the same among the three groups of patients. Finally, when bovine serum albumin was substituted for thyroglobulin from each of the patients, iodination of bovine serum albumin was several times greater with the particulate fraction obtained from toxic diffuse goiter tissue than with that obtained from normal tissue. The guaiacol-oxidizing activity oty. These results suggest that in vitro iodination of thyroglobulin is increased in toxic diffuse goiter even when patients are made euthyroid by treatment with thionamide drugs as well as when they are given additional T3 for 10 days before operation. The increase in iodination of thyroglobulin appears to be due to an increase in peroxidase activity in the particulate fraction.
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PMID:Iodinating activity of thyroid tissue in toxic diffuse goiter. 57 14

A principle for determination of the vacant amount of the high-affinity bilirubin binding site on serum albumin in the newborn is proposed: A small amount of monoacetyl-4,4'-diaminodiphenylsulphone (MADDS) is added to the serum sample and the equilibrium of binding of this substance is assessed by measuring the rate of dialysis into another volume of the same serum. It is shown that MADDS is bound selectively to the specific bilirubin site. Results obtained after addition of varying amounts of five drugs and of oleate are compared with those found by the peroxidase method. Good agreement is found although certain deviations are encountered, as expected in the case of allosteric affects. Free bilirubin concentrations can be calculated from the results.
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PMID:Determination of the vacant amount of high-affinity bilirubin binding site on serum albumin. 58 Mar 42

Human salivary proteins were enzymically iodinated by the 125I-lactoperoxidase system. The proteins were than subjected to DEAE-cellulose column chromatography, preparative column electrofocusing and thin-layer polyacrylamide-gel electrofocusing. The radioactivity in the resolved protein pools and bands was determined. Results show that salivary proteins differ in their susceptibility to iodination carried out by this enzymic method. Two major iodine-binding protein fractions were discovered: one behaved like serum albumin on electrofocusing and was most susceptible to iodination by lactoperoxidase, and other had pI characteristics similar to those of salivary amylase. The physiological significance of the iodination of salivary proteins, which can also take place in vivo, is discussed.
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PMID:Enzymically iodinated human salivary proteins. Fractionation and characterization by column chromatography and electrofocusing. 58 55

Binding of bilirubin to human serum albumin was studied by estimation of the free bilirubin concentration from the rate of oxidation with hydrogen peroxide and peroxidase, and by spectrophotometry: nI = 1, kI = 7 x 10(7) l/mol; nII = 1, kII = 5 x 10)5) l/mol, at pH 7.4, 37 degrees C, ionic strength 0.1. Palmitate or oleate in excess of 4 mol per mol albumin, influences the high-affinity binding of bilirubin as described by an empirical equation. Theoretical consideration of competitive displacement of a biologically active substance, firmly bound in an inactive state to a macromolecular carrier, demonstrates that significant displacement may occur on addition of another ligand with a lower binding constant. Displacement of bilirubin from its high-infinity site by fatty acids and drugs is thermodynamically feasible and probably clinically important.
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PMID:Binding of bilirubin and long-chain fatty acids to human serum albumin with general remarks on displacement of firmly bound ligands. 61 51

The distribution of gonadotropin-releasing hormone (GnRH) was studied immunohistochemically in the brain of the adult mouse with the peroxidase-antiperoxidase (PAP) method. Primary antisera were prepared against unconjugated synthetic GnRH and GnRH conjugated to limpet hemocyanin or bovine serum albumin. GnRH was localized in the organum vasculosum of the lamina terminalis (OVLT), with the greatest amount being found ventral to the cephalic end of the third ventricle. In the cephalic region of the median eminence, it was concentrated bilaterally in longitudinal bands located dorsal to the tuberoinfundibular sulci. More caudally, near the junction of the infundibulum with the brain, GnRH accumulated over the apex of the tuberoinfundibular sulci, with several foci being scattered from this region medially to the ependyma of the third ventricle. The greatest aggregation of GnRH occurred in the psotinfundibular median eminence in an area extending from the floor of the third ventricle to the ventral surface of the brain. In the caudal median eminence, GnRH was arranged in a narrow ventral band that crossed the midline. GnRH appeared to be located in axonal processes and terminals of the OVLT and median eminence; the structures observed were granular. GnRH was not localized within the neuronal cell bodies of any hypothalamic nuclei. When one antiserum to conjugated GnRH was used at high concentration, the cytoplasm of ependymal cell bodies and tanycyte processes was stained more intensely than the general background, but, with absorption and/or dilution of the antiseru, this staining was shown to be nonspecific.
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PMID:Distribution of gonadotropin-releasing hormone in the mouse brain as revealed by immunohistochemistry. 77 98

A comparative study of the secondary reaction of popliteal lymph nodes in young and adult rats was carried out. In one group of experiments secondary reaction was induced by bovine serum albumin (BSA), in the other one by peroxidase from horseradish. Antigen was administered with Freund adjuvant. It was established that the index of popliteal lymph nodes in a secondary reaction induced by BSA does not change with the increasing age. The incidence of antibody-producing cells in young and adult rats is the same. In the cytoplasma and mitochondria of the antibody-producing cells of the adult animals degenerative changes were observed. In the secondary reaction brought about by peroxidase intracytoplasmatic localization of the antibody in the young and adult animals did not reveal any differences.
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PMID:[Immunofluorescence and immunoelectron microscopic study of changes occurring in secondary reaction of popliteal lymph nodes in young and old rats]. 78 24

Antibodies to 5-bromodeoxyuridine (BrdU) or iododeoxyuridine may be used to identify cells or regions of chromosomes in which de novo deoxyribonucleic acid synthesis has occurred. The antibodies to BrdU were produced in rabbits by injection of the antigen, a conjugate between bovine serum albumin and bromouridine (BrU), or iodouridine. Specific antibodies were produced by affinity chromatography on AH-Sepharose 4B to which had been coupled BrU. Anti-BrU cross-reacts with iodeodeoxyuridine. Indirect antibody techniques have been used to monitor deoxyribonucleic acid synthesis in nuclei; anti-BrdU treatment was followed by goat anti-rabbit immunoglobulin G labeled with either fluorescein or horseradish peroxidase. By use of these techniques, labeling indices were determined in cell cultures which had been pulsed with 3H-BrdU. The immunologic technique compared favorably with the autoradiographic methods performed concurrently on the same cultures. Metaphase chromosomes from synchronous CHO cell which had been pulse labled with BrdU at different time intervals during S phase were subjected to these immunologic procedures. Chromosome banding was observed with both the fluoresence and peroxidase methods. Chromosomes from cells not containing BrdU did not exhibit banding.
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PMID:Deoxyribonucleic acid replication in single cells and chromosomes by immunologic techniques. 81 28

Conventional protein iodination involves the addition of an oxidizing agent to the protein solution. Through the use of the acylating agent N-succinimidyl-3(4-hydroxyphenyl)propionate, labeling can be accomplished without subjecting the protein to oxidizing conditions. Fibrinogen and serum albumin labeled with 131I and 77Br by this technique were compared with each other and with 125I-protein prepared by direct iodination using the ICI, chloramine-T, and lactoperoxidase methods. Iodinated proteins have two drawbacks: the high radiation dose accompanying 125I and 131I, and the ease of hydrolysis of the weak carbon-iodine bond. These drawbacks can be overcome by using 56-hr 77Br.
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PMID:In vitro stability and in vivo clearance of fibrinogen or serum albumin labeled with 77Br, 131I, or 125I by direct or indirect synthetic methods. 83 78

The association constants for the binding of bilirubin to human serum albumin (HSA) have been determined at four different temperatures by measurements of the rate of the peroxidase catalyzed oxidation of unbound bilirubin. The change of enthalpy is determined from a van't Hoff plot (ln Kass versus 1/T) to about -13.5 kcal/mol. deltaG degrees is calculated from the binding constants, and deltaS degrees is obtained from: deltaG degrees = deltaH degrees--TdeltaS degrees. The results show that the large negative deltaG degrees (--11 kcal/mol) for binding of bilirubin to HSA is a consequence of the negative deltaH degrees. The entropy was found to be about--8.5 cal/mol/degree and tends to diminish the numerical value of deltaG degrees. The binding constant has also been determined at varying ionic strength. The results show a decrease in binding for increasing salt concentration. The data from the two sets of experiments suggest that hydrogen bonds and salt linkages rather than hydrophobic interactions are the main factor in the binding of bilirubin to its primary site on HSA.
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PMID:Studies of the affinity of human serum albumin for binding of bilirubin at different temperatures and ionic strength. 84 42

Mice infected with Schistosoma mansoni were immunized against human type B Rh-positive (B+) RBC, bovine serum albumin, or horseradish peroxidase. Adult parasites, recovered by perfusion, extensively washed, and incubated in their respective antigens, selectively bound to their tegumental surfaces only those antigens to which their murine host had been immunized. All controls supported the specificity of those reactions leading to the conclusion that adult S. mansoni in mice have the ability to adsorb heterospecific antibody onto their tegumental surfaces. These surface immunoglobulins were lost within 10 min when complexed with theri antigens or within 2.5 hr when incubated at 37 degrees C. Parasites that had lost their tegumental immunoglobulins regained them when incubated in normal mouse or rat anti-human type B Rh-negative (B-) RBC serum. Those parasites that had their surface immunoglobulins reconstituted with rat anti-human B- serum specifically bound human B- RBC, suggesting the possible presence of Fc receptors on adult S. mansoni.
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PMID:Evidence for adsorption of heterospecific host immunoglobulin on the tegument of Schistosoma mansoni. 91 83


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