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)

220 MHz proton Fourier transform (FT) NMR with quadrature phase detection (QPD) technique is applied to observe largely hyperfine-shifted signals of various hemoproteins and hemoenzymes in ferric high-spin state. The binding of F-, OCN-, SCN-, and CH3OH to the ferric heme iron in high-spin state in various hemoproteins has been studied by the use of FT/QPD technique at 220 MHz. The binding of formate ion to metmyoglobin (metMb) has also been studied. The spectrum of the formate complex was compared with that of hemoglobin M Milwaukee where carboxylate groups are bound to the hemes of the beta subunits. The acid-base transition of ferric myoglobin (Mb) was confirmed by monitoring the pH-dependent shift of the heme side methyl signals with the reflection point at pH 9.1. This finding is analyzed on the basis of rapid exchange between alkaline (low spin) and acidic (high spin) forms accompanied by the dissociation and association of one proton in the ferric Mb. The structure of the heme environment of ferric horseradish peroxidase (HRP) was studied. The pH-dependent features of NMR spectra of the ferric enzyme and its complexes with cyanide and azide were discussed in terms of heme environmental structures, comparing with the case of metMb. The results were interpreted as follows: There exists an ionizable amino group near the heme responsible for the ligand binding reactions of the enzyme, which modulates the entry of external azide to the heme iron through protolytic equilibrium of this group. The pK value of this group was determined to be 5.9 by monitoring the pH-dependent shift of the heme peripheral methyl signals of the native enzyme, indicating that the group is probably a histidyl residue. Acid-alkaline transition of metMb was confirmed to associate with the proton dissociation of an iron-bound water molecule, whereas in HRP, pH-dependent spin state change characterized by pK 11 is attributed not to the simple protolytic reaction of the iron-bound water but to the direct coordination of an amino acid residue of the polypeptide chain to the ferric heme iron. Histidyl imidazole is a possible candidate for the new sixth iron ligand in alkaline peroxidase above pH 11. Interaction of HRP with electron donor(indolepropionic acid, IPA) was also studied. The hyperfine-shifted proton signals of the heme peripheral groups of the enzyme showed a small but significant shift with stepwise additions of IPA, indicating that the donor binds at a specific site of HRP. There results are interpreted in terms of the interaction between the enzyme and the donor at the heme edge site.
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PMID:Nuclear magnetic resonance studies of high-spin ferric hemoproteins. 2 54

The localization of peroxidase activity in methanol-grown cells of the yeast Hansenula polymorphia has been studied by a method based on cytochemical staining with diaminobenzidine (DAB). The oxidation product of DAB occurred in microbodies, which characteristically develop growth on or methanol, and in the intracristate space of the mitochondria. The staining of microbodies was H2O2 dependent, appeared to be optimal at pH 10.5, diminished below pH 10 and was inhibited by 20 mM 3-amino 1,2,4 triazole (AT). In contrast to these observations, the reaction in the mitochondria was not H2O2 dependent and not notably affected by differences in pH in the range of 8.5 to 10.5. Microbodies and mitochondria were also stained when H2O2 was replaced by methanol. Appropriate control experiments indicated that in this case methanol oxidase generated the H2O2 for the peroxidative conversion of DAB by catalase. These results suggest that catalase is located in the microbodies of methanol-grown yeasts. A model for a possible physiological function of the microbodies during growth on methanol is put forward.
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PMID:Cytochemical localization of catalase activity in methanol-grown Hansenula polymorpha. 5 39

A selective staining of hemoglobin in erythroid cell series was achieved by use of Sudan Black B (modified method of Sheehan and Storey) if optimal amount of hydrogen peroxide was added to the staining mixture. The effect of some inhibitory agents (KCN, wet heat, pH) on this staining as well as on the Lepehne's pseudoperoxidase reaction for hemoglobin was similar. Both reactions were more resistant to these factors than the peroxidase reactions and sudanophilia in granulocytes in which both could be blocked by the pretreatment with absolute methanol. Moreover the effect of some extraction procedures for lipids on both myeloperoxidase reactions and sudanophilia was investigated. The results support the view that the sudanophilia in granulocytes is due to their peroxidase activity and for the staining of hemoglobin by use of Sudan Black B with H2O2 its pseudoperoxidase activity is responsible. In addition the effect of the substitution of phenolphosphate by dihydroxybenzenes on granulocyte sudanophilia is reported.
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PMID:Peroxidase and pseudoperoxidase reactions in relation to sudanophilia. 7 Dec 89

The ultrastructural localization of the activities of two enzyme systems in the culture forms of Leishmania donovani was shown by means of the diaminobenzidine techniques. The consistent deposition of electron dense reaction product of DAB oxidation without H2O2 in the kinetoplast and mitochondrial cristae and membranes was taken as evidence of the presence of cytochrome oxidase activity and cytochrome c. In the presence of H2O2, a more intense DAB oxidation was attributed to the activity of a peroxidase, possibly cytochrome c peroxidase. Mitochondrial and kinetoplast reactions to DAB were completely inhibited by KCN, methanol-nitroprusside, and by heating to 50 degrees C for 10 min. On the other hand, no inhibitory effect was observed with 100 mM 3-amino-1,2,4-triazole. Under all conditions of incubation tested, the microbodies were completely unreactive to DAB staining, which was utilized as the basis for their identification. These organelles are rounded, moderately electron-opaque bodies with a finely granular matrix and fine tubules or cores and are limited by a single membrane. Under normal staining method, the microbodies were indistinguishable from the rounded sections of mitochondria.
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PMID:Ultrastructural localization of diaminobenzidine reactivity in leishmania donovani promastigotes. 19 23

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

Mononuclear cells from seven patients with hairy cells leukaemia were examined for features suggestive of either a lymphocytic or monocytic origin. Immunofluorescent staining of both methanol fixed and incubated cells, using monospecific antisera, revealed a predominant cell-associated immunoglobulin in each case. Three were positive for mu and kappa chains, two for gamma and kappa chains, one for delta and kappa chain determinants and one reacted only with antigamma chain serum. Formation of EAC rosettes, a feature of both B lymphocytes and monocytes, was variable. T cells, as judged by E rosettes, were not elevated in any patient. Phytohaemagglutinin reactivity was normal in six and depressed in one case. With the exception of minimal activity in assays for glass adherence and latex particle phagocytosis, none of the cells showed features typical of monocytes. Hairy cells were negative by peroxidase stain and lacked the electron microscopic characteristics of monocytes. They did not react in either rosette or phagocytic assays with anti-A or anti-D coated erythrocytes nor did they elaborate granulocyte colony stimulating factor, a monocyte-derived in vitro granulopoietin. Although unequivocal classification of these abnormal cells is not possible, the data storngly suggests that this represents a variant of a B lymphocytic neoplasm.
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PMID:Hairy cell leukaemia: seven cases with probable B-lymphocytic origin. 30 39

Intrinsic tissue peroxidase activity can be more or less successfully destroyed by methanol-H2O2 treatment. It has been found, however, in our laboratory that horseradish peroxidase (HRP) coupled to antibody will bind to some tissue components on a nonspecific basis and remain to take part in the histochemical stain. This contributes considerably to the background. This difficulty can be largely overcome if the tissues are pretreated with a solution of horseradish peroxidase which binds with nonspecific tissue sites. The adsorbed enzyme, along with the intrinsic peroxidase, can then be successfully inactivated by methanol-H2O2 treatment. By this method of blocking, there is considerable reduction in background staining.
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PMID:Use of horseradish peroxidase to block nonspecific enzyme uptake in immunoperoxidase microscopy. 35 48

The radioimmunoassay for LH-RH would aid greatly in the assessment of hypothalamic function. The anti-LH-RH was prepared by immunizing rabbits with LH-RH conjugate of BSA. 125I-LH-RH was prepared by the lactoperoxidase method and Sephadex G-10 column chromatography. The double antibody RIA technique was employed. On the assay of biological materials, LH-RH was extracted by methanol because LH-RH was rapidly destroyed in the serum, and this breakdown could not be prevented by benzamidine or 2,3-dimercaptopropranol. Sensitivity of this RIA system ranged from 10 tp 104 pg/ml, and the coefficient of variations of intra- and interassay were 12.9% and 9.% respectively. The serum LH-RH levels of men in a normal gonad state were below 10 pg/ml, and those of women in a normal gonad state in the early follicular or luteal phase were below 50 pg/ml. Whereas those of postmenopausal or castrated women were increased, and were highest in women with several gonadal disturbed states. The disappearance curve of LH-RH in women was characterized by two exponentials, t(1/2) of the initial component was 4.9 min, and that of the second component 24.6 min. Urinary excretion of exogenously administered LH-RH was also studied.
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PMID:[Studies on the measurements of LH-releasing hormone (LH-RH) by radioimmunoassay (RIA) (author's transl)]. 76 70

Peroxidase activity was investigated by the use of diaminobenzidine method in fixed cells of Prototheca moriformis. A strong peroxidase activity was observed in the mitochondria. DAB staining was unaffected by KCN, aminotriazole and antimycin A, but it was completely inhibitied by methanol-nitroferricyanide.
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PMID:Peroxidase activity in mitochondria of Prototheca moriformis. 84 56

Distribution of peroxidase activity in the mitochondria of the miracidium of the blood fluke, Schistosoma mansoni, was investigated cytochemically using the diaminobenzidine (DAB) technique. Re-action product was localized in the mitochondria of this larvae stage at pH 7.4 and 9.7. The reaction was peroxide-dependent and insensitive to either potassium cyanide, sodium azide, or 3-amino-1,2,4-triazole at the concentrations used. The reaction was inactivated by heat and by pretreatment with methanol-nitro-ferricyanide, and inhibitor of peroxidase. A perioxide-independent reaction was also observed in the mitochondria. This latter reaction was sensitive to potassium cyanide and sodium azide. It is hypothesized that the peroxidase either may act where peroxide is an electron acceptor in a flavoprotein-linked system or may be a vestige of a more primitive pathway. No peroxidase activity was observed in the mitochondria of other stages of the life cycle of the worm.
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PMID:Cytochemical localization of peroxidase activity in the miracidium of Schistosoma mansoni. 116 46


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