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)

A new enzyme which catalyzes the oxidation of the side chain of tryptophan and other indole derivatives, has been purified to apparent homogeneity from Pseudomonas and crystallized. The overall purification was about 25-fold with a yield of 4.5%. The purified enzyme was apparently homogeneous as judged by polyacrylamide gel electrophoresis. The molecular weight estimated by gel filtration was approximately 280,000 and sedimentation coefficient (S20,w) was 11 by sucrose density gradient ultracentrifugation. The absorption spectra indicated that the enzyme was a hemoprotein. The purified enzyme was shown to catalyze the reaction in which 1 mol each of NH3 and CO2 was formed at the expense of 1 mol each of L-tryptophan and molecular oxygen. Neither peroxidase nor catalase activity was detected in the purified enzyme and no formation of H2O2 was observed during the enzyme reaction. The product(s) of the reaction was unstable but was converted to and was identified as its stable quinoxaline derivative, 2-(3-indolyl)quinoxaline, in the presence of o-phenylenediamine. These results indicate that the product of the reaction was 3-indolylglycoaldehyde or 3-indolylglyoxal. A variety of other indole derivatives such as D-tryptophan, 5-hydroxyl-L-tryptophan, tryptamine, serotonin, melatonin, N-acetyl-L-tryptophan, N-acetyl-L-tryptophanamide, 3-indoleacetamide, 3-indolelactic acid, 3-indolepropionic acid, 3-indoleethanol, and skatole were also substrates.
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PMID:Crystalline hemoprotein from Pseudomonas that catalyzes oxidation of side chain of tryptophan and other indole derivatives. 1 95

A selectively Fc gamma-binding protein was isolated from purified and radioiodinated cell membranes from two cases of B-type chronic lymphocytic leukemia and one case of B-type prolymphocytic leukemia by binding to IgG aggregates, horseradish peroxidase-anti-peroxidase IgG complexes, and sheep erythrocyte membrane sheets densely coated with IgG. This protein could not be isolated from the cell membranes of an Fc gamma-receptor-negative chronic lymphocytic leukemia of the T type or from membranes of human erythrocytes. The Fc gamma-binding protein was efficiently solubilized by a mixture of Na-EDTA and 2-mercaptoethanol, but not with one of these agents alone, indicating that both divalent cations and disulfide bridges are involved in the linkage of the Fc gamma-binding protein to the cell membrane. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the Fc gamma-binding protein revealed an apparent mol wt of 28,000 and in isoelectric focusing it showed an isoelectric point of 5.5. The electrophoretic mobility of the 28,000-dalton protein did not change after reduction and alkylation. It was determined that the NH2-terminal amino acid of the protein was glycine. The isolated protein was unable to agglutinate antibody-coated erythrocytes. These findings suggest that the 28,000-dalton IgG-affined protein was composed to O2-enriched buffer lacking reducing agents, the 28,000-dalton protein aggregated to a 115,000-dalton molecule. The isolated Fc gamma-binding protein proved to be different from C1q or its subunits.
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PMID:Properties of an Fc gamma-binding protein isolated from human leukemic B cells. 9 52

The effects of K2PtCl4, cis-Pt(NH3)2Cl2, and trans-Pt(NH3)2Cl2 on the activities of glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, dihydrofolate reductase, fructose-1,6-bisphosphate aldolase, catalase, tyrosinase, and peroxidase have been investigated. All of the enzymes which are thought to have essential sulfhydryl groups (glyceraldehyde-3-phosphate dehydrogenase, aldolase, and glucose-6-phosphate dehydrogenase) were significantly inhibited by K2PtCl4. The other four enzymes studied are not known to have essential sulfhydryl groups, and were not significantly affected by the Pt compounds under the conditions employed. Glyceraldehyde-3-phosphate dehydrogenase was the only enzyme inhibited by all three Pt compounds tested, with K2PtCl4 being the most effective and cis-Pt(NH3)2Cl2 the least effective inhibitor. Semilogarithmic plots of residual activity versus inhibition time indicated that the inhibition reactions were not simple first-order processes, except for the inhibition of glucose-6-phosphate dehydrogenase by K2PtCl4 which appeared to be first-order with respect to enzyme concentration.
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PMID:The effects of platinum complexes on seven enzymes. 11 85

Only 5 to 10% of the apolipoprotein A-I (ApoA-I) of intact high density lipoprotein (HDL) is detectable by radioimmunoassay. In addition, when isolated ApoA-I is recombined with lipids in vitro, its immunologic reactivity is decreased by 30 to 95%. Thus, ApoA-I is less reactive immunologically in the presence of lipids. Our aim was to ascertain whether the COOH- or NH2-terminal regions of ApoA-I were equally reactive in intact HDL2. CNBr fragments of ApoA-I were produced by the method of Baker et al. (Baker, H.N., Jackson, R.L., and Gotto, A.M. (1973) Biochemistry 12, 3866-3871) and iodinated with lactoperoxidase. Double-antibody radioimmunoassays were set up using anti ApoA-I antisera and 125I-CNBr I (COOH-terminal region) or 125I-CNBr II (NH2-terminal). Both labels were bound by the antisera. Affinity columns were prepared by binding CNBr I or CNBr II to Sepharose 4B. Antibodies specific against CNBr I or CNBr II were isolated by means of these columns, suggesting that ApoA-I had at least two antigenic sites. In other assays using labeled fragments and anti ApoA-I antisera, 125I-CNBr I was displaced by CNBr I, ApoA-I , and HDL2 but not CNBr II. Conversely, 125I-CNBr II was displaced by CNBr II, ApoA-I, and HDL2 but not by CNBr I. Thus the assays were region-specific. The reactivities of isolated ApoA-I and the ApoA-I in intact HDL2-ApoA-I) were compared in these assays. On a molar basis, HDL2-ApoA-I was consistently more reactive (2- to 5-fold) in the 125I-CNBr I than in the 125I-CNBr II assays. The findings suggest (a) that the two terminal regions of ApoA-I are immunologically distinct, (b) that the two regions can be assayed independently of each other in intact HDL2, and (c) that the COOH-terminal region is more reactive immunologically than is the NH2-terminal. The results are compatible with a more "exposed" position for the COOH-terminal region on the surface of HDL2.
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PMID:Structure of high density lipoprotein. The immunologic reactivities of the COOH- and NH2-terminal regions of apolipoprotein A-I. 18 10

Oxygen uptake and reduction of C2H2 by bacteroids was found to be inhibited by low concentrations of cyanide and azide. However, oxygen uptake was not completely suppressed even by 10(-3) M KCN. Cyanide-resistant respiration was not inhibited by salicyl-hydroxamic acid, and seemed to be accomplished at the account of autoxidable flavo-proteins. A small light-reversible inhibition of respiration by carbon monoxide was found only in the bacteroids with a high rate of nitrogen fixation. Rotenone, antimycin A, and tenoyltrifluoroacetone inhibited oxygen uptake and methylene reduction. Nitrogen fixation, but not respiration, was inhibited by 2,4-dinitrophenol. An electron-transport chain coupled with phosphorylation is supposed to be built into the membranes of the bacteroids. The activity of peroxidase and cytochrome peroxidase was demonstrated in the bacteroids.
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PMID:[Inhibitory analysis of the respiration of bacteroids from the nodules of yellow lupine]. 18 Mar 85

The chlorination of dipeptides by the myeloperoxidase/H2O2/Cl- system takes place at the N-terminal amino group, whereas no chlorination of the amide nitrogen of the peptide bond can be observed. The N-terminal amino group is chlorinated to N-monochloroamine or/and N-dichloroamine. N-Monochloropeptides were the main products at higher pH values, at lower pH at mixture of N-monochloropeptides and N-dichloropeptides was formed owing to the dismutation of N-monochloroamine to N-dichloroamine. N-Monochloropeptides decompose, yielding NH3 and the corresponding N-(2-oxoacyl)amino acids. N-Dichlorodipeptides decompose faster but to nitriles and the free C-terminal amino acids. N-Dichloroglycyl-amino acid decomposes through a relatively stable intermediate (cyano-formylamino acid) to hydrogen cyanide, cyanogen chloride and the free C-terminal amino acid. Insulin chlorination also yields N-terminal glycyl and phenylalanyl N-monochloro derivatives, which deaminate to glyoxylyl and phenylpyruvyl residues.
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PMID:N-(2-Oxoacyl)amino acids and nitriles as final products of dipeptide chlorination mediated by the myeloperoxidase/H2O2/Cl- system. 21 10

The NH2-terminal sequence of bovine parathyroid hormone (1-84) was localized with different immunocytochemical methods on the light and electron microscopic level in bovine parathyroid glands and in isolated bovine parathyroid parenchymal cells. The peroxidase labeled staphylococcal protein A and the peroxidase anti-peroxidase method were found to be advantageous for light and electron microscopic localization, respectively. Reaction product was found light microscopically in the cytoplasma of the parenchymal cells and electron microscopically largely over the secretion granules of the parenchymal cells. The immunoreactive sites were subsequently identified to represent only intact parathyroid hormone (1-84) by gel electrophoresis derived enzyme linked immunosorbent assay.
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PMID:Identification of immunoreactive sites in bovine parathyroid cells to antibodies raised against the NH2-terminal sequence of parathyroid hormone. 38 28

Modification of epsilon-NH2 groups of lysine residues in horseradish peroxidase by acetic, propionic, butyric, valeric and succinic anhydrides and trinitrobenzenesulfonic acid (TNBS) is carried out. All the anhydrides modify at 0 degrees C four epsilon-NH2 lysine groups, and TNBS--three groups. TNBS modifies all 6 peroxidase epsilon-NH2 groups at 40 degrees C. Possible spacing of lysine epsilon-NH2 groups in the enzyme molecule is discussed.
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PMID:[Chemical modification of epsilon-NH2 groups of lysine residues in horseradish peroxidase. Accessibility of these groups to different modifying agents]. 65 3

The 95,000-dalton polypeptide in human red blood cell membranes constitutes about 25% of the membrane protein. Previous labeling studies have shown that different regions of this polypeptide are exposed to the inside and outside of the cell and have suggested a role for the protein in anion exchange across the membrane. This polypeptide has been fragmented by chymotrypsin digestion of intact red cells and by treatment of purified polypeptide with 2-nitro-5-thiocyanobenzoic acid, hydroxylamine, and N-bromosuccinimide. The sites of cleavage by each of these reagents have been located relative to the NH-2 and COOH-terminals of the intact 95,000-dalton polypeptide. Polypeptide obtained from cells labeled with 1-isothiocyanate-4-benzene [35S]sulfonic acid (an inhibitor of anion transport), 125I and lactoperoxidase, or 32P has been similarly fragmented and these labels have been assigned to specific regions of the polypeptide. There are at least two sites of phosphorylation of the polypeptide; the major sites lies within 10,000 daltons of the NH2-terminal requiring that this portion of the polypeptide lie inside the cell. Sites of chymotrypsin cleavage and 125I and lactoperoxidase labeling are in a 7,000-dalton region toward the COOH-terminal of the polypeptide; this region must lie outside the cell. Between these two regions the polypeptide must traverse the lipid bilayer an odd number of times. 1-Isothiocyanate-4-benzenesulfonic acid also labels the protein near the site of chymotrypsin cleavage.
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PMID:Fragmentation of the 95,000-dalton transmembrane polypeptide in human erythrocyte membranes. 95 79

Three types of organic polymers and bead-shape silica gels were activated by graft polymerization of 2,3-epoxypropyl methacrylate; in some cases, epoxide groups on the support surface were modified to NH2 groups. Eight active matrices so obtained were assessed as supports for immobilized enzymes using peroxidase, glucoamylase and urease. The immobilization yield of protein and specific activities of enzymes were better with supports containing NH2 groups than with those containing epoxide spacer arms. Maximum enzyme immobilization and storage stabilities were obtained with silica-gel beads activated by graft polymerization of 2,3-epoxypropyl methacrylate. With all eight matrices tested, the immobilized enzymes showed good stability with not less than 82% of the original activity persisting after 28 days. The developed matrices have potential for use in process-scale biotechnological operations.
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PMID:Immobilization of enzymes to porous-bead polymers and silica gels activated by graft polymerization of 2,3-epoxypropyl methacrylate. 136 57


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