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

The authors subjected peripheral blood smears of Torpedoes to cytochemical analysis of lipids, protein, neutral and acid polysaccahrides and of some enzymatic activities, i.e. adenosine triphosphatase (ATP-ase), acid and alkaline phosphatase, aliesterase and peroxidase. It was found that neutrophilic granulocytes are intensely PAS and aliesterase positive and weakly ATP-ase positive. Eosinophilic granulocytes show the presence of neutral polysaccharides in the matrix (which is PAS positive) and strong ATP-ase and acid phosphatase activities in the granules. Lymphocytes sometimes contain weakly PAS and aliesterase positive granules. Monocytes show some small PAS positive granules and weak acid phosphatase and aliesterase activities. Thrombocytes contain some peripheral granules which are PAS positive and slightly ATP-ase positive. There are no transitional forms between the various cellular types. The results confirm the classification of leukocytes of Torpedoes into neutrophilic granulocytes, eosinophilic granulocytes, lymphocytes, monocytes and thrombocytes and contribute some informations about the histoenzymatic content of Elasmobranch leukocytes.
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PMID:Cytochemical identification of the leukocytes of torpedoes (Torpedo marmorata Risso and Torpedo ocellata Rafinisque). 636 Jan 39

A simplified micro ELISA procedure to measure platelet-associated IgG is described. The platelet-bound IgG first is extracted into the fluid phase by solubilizing washed platelets in 0.1% triton X-100. The solubilized IgG in the extract and IgG standards are incubated in microtiter wells previously coated with antihuman IgG. The IgG in the standards and extract bind to the solid phase antihuman IgG. The bound IgG then is measured by the addition of peroxidase labeled antihuman IgG and appropriate substrate. With this method platelets from normal controls were found to have 1.7 +/- 0.6 fg IgG/platelet (mean +/- SD). Platelets from patients with ATP had values that were two to seven times the control values. The relative advantage of this technic is discussed.
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PMID:A simplified micro ELISA procedure for the measurement of platelet-associated IgG (PAIgG). 636 94

Sarcoplasmic reticulum (SR) vesicles from ovine skeletal muscle were iodinated with the use of immobilized lactoperoxidase to determine the location of proteins in the membrane and to observe any changes resulting from post-mortem electrical stimulation. The labelling pattern of the non-stimulated SR preparations was esentially the same as that observed previously for white muscle SR of rabbit. Most of the membrane protein were labelled, except for the high-affinity calcium-binding protein. Electrical stimulation, however, resulted in an increased labelling of calsequestrin suggesting that this protein is more exposed as a result of such treatment. Certain activities of the adenosinetriphosphatase were affected by electrical stimulation. Both the steady-state concentration of phosphoenzyme and the ATP in equilibrium Pi exchange reaction were significantly reduced by electrical stimulation. It is not known if this alteration in the membrane is responsible for the reduced activity of the SR and thus the greater rate of post-mortem pH in electrically stimulated muscle.
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PMID:Effect of post-mortem electrical stimulation on ovine sarcoplasmic reticulum vesicles. 644 97

Insulin receptors from rat hepatoma cells were studied by the three following methods. Firstly, the alpha subunit (Mr 130000) was labelled using a 125I-photoreactive insulin analogue and UV irradiation. Secondly, using phosphorylation of partially purified and immunoprecipitated receptors with [gamma-32P]ATP, the beta subunit (Mr 95000) was labelled. Thirdly, both alpha and beta subunits were labelled by surface iodination catalysed by lactoperoxidase followed by cell solubilization and immunoprecipitation of the receptor with anti-receptor antibodies. The results show that the native insulin receptor exists under different forms: free alpha and beta subunits and the following combinations of disulphide-linked oligomers: alpha beta, alpha 2, alpha 2 beta and alpha 2 beta 2. In addition, it appears that there is at least one insulin binding site per alpha subunit, and that the alpha and beta subunits may be in close physical association in the plasma membrane even when they are not linked by disulphide bonds. In intact cells, only the alpha subunit is sensitive to extracellular proteases that cleave preferentially the region of the alpha subunit bearing the sulphydryl groups responsible for the interchain binding.
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PMID:Subunit arrangement of insulin receptors in hepatoma cells. 674 84

An L-amino acid oxidase (L-amino-acid oxygen oxidoreductase (deaminating), EC 1.4.3.2) from the blue-green alga Anacystis nidulans has been purified to homogeneity with an overall yield of about 10%. Purification included ammonium sulfate fractionation and CM-Sephadex, DEAE-Sephadex, and hydroxyapatite chromatography. The purified enzyme has an absorption spectrum which is characteristic of a flavoprotein, and contains 1 mol FAD per mol enzyme. The native enzyme has a molecular weight of 98 000 as determined by gel exclusion chromatography. Electrophoresis in SDS-polyacrylamide gels gives a single protein band corresponding to a molecular weight of 49 000, which suggests that the native enzyme is composed of 2 subunits of equal molecular weight. As previously demonstrated, the enzyme catalyzes the oxidative deamination of the basic amino acids: L-arginine, L-lysine, L-ornithine and L-histidine. In the presence of catalase and of any of these amino acids, 0.5 mol O2 is consumed, and 1 mol ammonia is formed for each mol amino acid oxidized. HCN is formed from L-histidine when the L-amino acid oxidase is supplemented with peroxidase. In addition to the unusual substrate specificity of this L-amino acid ozidase, it also has an unusual set of inhibitors including o-phenanthroline as well as divalent cations of which Cu2+, Zn2+, and Cd2+ are the most effective ones, but Mg2+ and Ca2+ also inhibit. This inhibition can be reversed by chelating agents such as EDTA. ATP and ADP, but not AMP, can also overcome the inhibition caused by Mg2+, for example. The inhibitory effect of cations can be demonstrated in vivo.
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PMID:Some properties of a basic L-amino-acid oxidase from Anacystis nidulans. 676 43

We describe the enzymic determination of free fatty acids in serum with use of acyl-CoA synthetase (EC l.2.1.3), acyl-CoA oxidase (no EC no. assigned) and peroxidase (EC 1.11.1.7). The free fatty acids are activated by acyl-CoA synthetase in the presence of ATP and coenzyme A. The acyl-CoA formed is oxidized by acyl-CoA oxidase to enoyl-CoA with simultaneous production of hydrogen peroxide, which is oxidatively coupled with 4-amino-antipyrine and 2,4-dibromphenol in the presence of peroxidase to yield a product that absorbs maximally at 505 nm. Standard curves prepared with various kinds of fatty acids are linear to at least 2.0 mmol/L and are practically congruent. Ascorbic acid or bilirubin interferes slightly. Results by the present method correlate well with those by the colorimetric method involving 2-(2-thiozolylazo)-p-cresol (r = 0.98). Replicate analyses of standard solution and of two kinds of control sera demonstrated the following between-assay precision: mean absorbance 0.224 (SD 0.002), CV 0.85%; mean concentration, 326 (SD 7.3) and 1076 (SD 22.7) mumol/L, CV 2.24 and 2.11%, respectively.
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PMID:Enzymic determination of free fatty acids in serum. 677 37

The role of secretory IgA antibodies in the antiviral and antibacterial defense of the higher respiratory tract has been widely demonstrated, and the IgA determination in the nasal secretion has become of the highest value in the clinical study. The mechanism by which IgA reaches nasal secretion through the mucosa is still a matter of discussion and neither hypothesis put forward by Tomasi (i.e. free filtration through the epithelic-connectival interstitium or transcellular transport plus active secretion) has so far been fully demonstrated. By using a horseradish peroxidase labeled IgG directed against human IgA we have performed, with suitable controls, a semi-quantitative study on semi-thin and thin section of the IgA behaviour at the level of human nasal mucosa. We have shown that IgA, made up and secreted in the connectival interstitium by specific plasma cells, would be taken up by endocytosis by epithelial cells, where it can be seen especially in the Golgi apparatus and in the large secretion granules. Since in the intracellular transport of pinocytic vesicles actin microfilaments and microtubules undoubtedly play a major role, with ATP utilisation, further studies using either physical factors (e.g. exposure to cold) effecting ATP utilisation or chemical ones (e.g. cytochalasin B and colchicine) depolymering respectively microfilaments and microtubules, should be performed in order to bring further proofs in favor of the active transport IgA mechanism suggested by our present investigations.
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PMID:IgA transport mechanism through the human nasal mucosa: an immunoenzymatic ultrastrutural study. 699 29

This study was designed to investigate the effects of ATP-MgCl2 when infused immediately 8 or 24 hr after 45 min of bilateral renal artery ischemia and to determine if an initial improvement in clearance of inulin (CIn) would be sustained throughout the course of recovery. In addition, the influence of ATP-MgCl2 on the pattern of recovery of whole kidney and single nephron function was assessed by determining the impact of this agent on proximal tubular pressure and transepithelial backleak. The postischemic administration of ATP-MgCl2 resulted in significantly enhanced recovery of CIn irrespective of the time of the infusion after the initial insult. This beneficial effect was sustained in that the ATP-MgCl2-treated rats had significantly better CIn 1, 3 and 7 days after the injury when compared to normal saline-treated animals. Moreover, single nephron inulin clearance (SNCIn) was better preserved than whole kidney CIn in both groups of animals and in the ATP-MgCl2-treated animals SNCIn was similar to control values even 1 day after the injury. The enhanced recovery of single nephron function in the ATP-MgCl2-treated animals resulted from reduced proximal tubular pressure and diminished backleak of tubular fluid. Animals given ATP-MgCl2 had better preservation of cellular morphology. Horseradish peroxidase was excluded from most epithelial cells and the interstitium in a manner similar to that seen in control animals while saline-treated rats demonstrated backleak of this tracer compound. Based on these studies, it appears that the beneficial effect of ATP-MgCl2 occurs because of the preservation of sublethally injured cells by augmentation of the process of recovery.
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PMID:Accelerated recovery of single nephron function by the postischemic infusion of ATP-MgCl2. 712 Jul 52

1 Vasoactive intestinal polypeptide (VIP, 0.01- MicroM) produced dose-related relaxations of the mouse anococcygeus muscle. 2 Following incubation with indomethacin (2.8 microM 1 h) adenosine 5'-triphosphate (ATP, 0.5-10 mM) produced dose-related relaxations of the mouse anococcygeus. 3 Haemolysed blood reduced inhibitory responses of the mouse anococcygeus to field stimulation but had no effect on relaxations to VIP or ATP. 4 Apamin (0.5 microM) had no effect on the relaxation of mouse anococcygeus to field stimulation, VIP, or ATP. 5 2-2'-Pyridylisatogen tosylate (PIT, 50 microM) itself reduced muscle tone but it did not abolish inhibitory responses to field stimulation, VIP, or ATP. 6 During prolonged inhibitory nerve stimulation the relaxation of the mouse anococcygeus in response to VIP was reduced greatly while that to ATP was unaffected. 7 Bundles of VIP-immunoreactive sites were detected in sections of the mouse anococcygeus treated by the peroxidase-antiperoxidase (PAP) immunocytochemical technique. 8 The results suggest that the mechanisms underlying non-adrenergic, non-cholinergic inhibitory transmission in the mouse anococcygeus are similar to those in the bovine retractor penis and unlike those in the guinea-pig taenia caeci. 9 The possibility that VIP or ATP might be involved in inhibitory neurotransmission in the mouse anococcygeus is discussed.
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PMID:The effects of vasoactive intestinal polypeptide and of adenosine 5'-triphosphate on the isolated anococcygeus muscle of the mouse. 712

The enzymatic activity of hexokinase (ATP : D-hexose 6-phosphotransferase, EC 2.7.1.1) decreased rapidly when the enzyme was exposed to the lactoperoxidase antimicrobial system (consisting of lactoperoxidase, H2O2 and SCN-). Inactivation did not begin until the reaction of one sulfhydryl group per hexokinase monomer was completed. Loss of enzyme activity accompanied the reaction of at least one additional sulfhydryl group per monomer. Covalent incorporation of 14C-labeled SCN- into hexokinase increased as the inactivation reaction progressed. The rate of the hexokinase activity loss dependent on temperature, pH and the presence of glucose and phosphate ion. When H2O2 and SCN- were applied to a Sepharose column bearing covalently attached lactoperoxidase, the column eluate inactivated hexokinase. This demonstrated that the lactoperoxidase molecule itself need not be in contact with hexokinase in order to catalyze hexokinase inactivation. The sulfhydryl-reactive oxidation product of SCN- which is generated by the column is sufficient. The results are consistent with a two-stage reaction in which the exposed, non-essential sulfhydryl groups on the hexokinase molecule react first to produce an enzymatically active but unstable form of hexokinase. This modified form of hexokinase then undergoes a spontaneous, temperature-dependent structural change, which allows reaction of previously shielded, essential sulfhydryl groups. The phenomenon described here suggests a possible mechanism for the antimicrobial effects of the lactoperoxidase system.
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PMID:Lactoperoxidase-catalyzed inactivation of hexokinase. 724 2


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