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)

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

HOCl, which is produced by the action of myeloperoxidase during the respiratory burst of stimulated neutrophils, was used as a cytotoxic reagent in P388D1 cells. Low concentrations of HOCl (10-20 microM) caused oxidation of plasma membrane sulfhydryls determined as decreased binding of iodoacetylated phycoerythrin. These same low concentrations of HOCl caused disturbance of various plasma membrane functions: they inactivated glucose and aminoisobutyric acid uptake, caused loss of cellular K+, and an increase in cell volume. It is likely that these changes were the consequence of plasma membrane SH-oxidation, since similar effects were observed with para-chloromercuriphenylsulfonate (pCMBS), a sulfhydryl reagent acting at the cell surface. Given in combination pCMBS and HOCl showed an additive effect. Higher doses of HOCl (greater than 50 microM) led to general oxidation of -SH, methionine and tryptophan residues, and formation of protein carbonyls. HOCl-induced loss of ATP and undegraded NAD was closely followed by cell lysis. In contrast, NAD degradation and ATP depletion caused by H2O2 preceded cell death by several hours. Formation of DNA strand breaks, a major factor of H2O2-induced injury, was not observed with HOCl. Thus targets of HOCl were distinct from those of H2O2 with the exception of glyceraldehyde-3-phosphate dehydrogenase, which was inactivated by both oxidants.
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PMID:Mechanisms of hypochlorite injury of target cells. 215 10

The Rho(D) antigen was recently identified as a 28,000 to 33,000 m.w. polypeptide expressed on the surface of human Rho(D)+ cells. We now show that 70 to 80% of the Rho(D) polypeptides remain firmly associated with the membrane skeleton (detergent-insoluble matrix) obtained after treatment of isolated membranes with Triton X-100. The same treatment solubilized most of the major sialoglycoprotein, glycophorin A. The membrane skeleton-bound Rho(D) polypeptides were not solubilized by procedures that dissociated spectrin, actin, and glyceraldehyde-3-phosphate dehydrogenase from the membrane. Affinity-purified 125I-labeled anti-Rho(D) antibodies bound to intact Rho(D)+ cells, Rho(D)+ membranes, and isolated membrane skeletons from Rho(D)+ cells, but not to Rho(D)- cells. The binding to Rho(D)+ cells was competitively inhibited efficiently by Rho(D)+ membranes and weakly by Rho(D)- membranes. When isolated unsealed Rho(D)+ and Rho(D)- membranes were labeled by lactoperoxidase-catalyzed iodination and solubilized in Triton X-100, Rho(D) polypeptides were immune precipitated only from Rho(D)+ membranes.
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PMID:Association of Rho(D) polypeptides with the membrane skeleton in Rho(D)-positive human red cells. 642 41

Approved type strains of Streptococcus sanguis, S. mitis, S. mutans, and S. salivarius were grown under aerobic and anaerobic conditions. The rate of hydrogen peroxide excretion, oxygen uptake, and acid production from glucose by washed-cell suspensions of these strains were studied, and the levels of enzymes in cell-free extracts which reduced oxygen, hydrogen peroxide, or hypothiocyanite (OSCN-) in the presence of NADH or NADPH were assayed. The effects of lactoperoxidase-thiocyanate-hydrogen peroxide on the rate of acid production and oxygen uptake by intact cells, the activity of glycolytic enzymes in cell-free extracts, and the levels of intracellular glycolytic intermediates were also studied. All strains consumed oxygen in the presence of glucose. S. sanguis, S. mitis, and anaerobically grown S. mutans excreted hydrogen peroxide. There was higher NADH oxidase and NADH peroxidase activity in aerobically grown cells than in anaerobically grown cells. NADPH oxidase activity was low in all species. Acid production, oxygen uptake, and, consequently, hydrogen peroxide excretion were inhibited in all the strains by lactoperoxidase-thiocyanate-hydrogen peroxide. S. sanguis and S. mitis had a higher capacity than S. mutans and S. salivarius to recover from this inhibition. Higher activity in the former strains of an NADH-OSCN oxidoreductase, which converted OSCN- into thiocyanate, explained this difference. The change in levels of intracellular glycolytic intermediates after inhibition of glycolysis by OSCN- and the actual activity of glycolytic enzymes in cell-free extracts in the presence of OSCN- indicated that the primary target of OSCN- in the glycolytic pathway was glyceraldehyde 3-phosphate dehydrogenase.
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PMID:Hydrogen peroxide excretion by oral streptococci and effect of lactoperoxidase-thiocyanate-hydrogen peroxide. 683 37

To understand the relationship between the structure and functions of the peroxidase of Arthromyces ramosus, a novel taxon of hyphomycete, and the evolutionary relationship of the A.ramosus peroxidase (ARP) with the other peroxidases, we isolated complementary and genomic DNA clones encoding ARP and characterized them. The sequence analyses of the ARP and cDNA coding for ARP showed that a mature ARP consists of 344 amino acids with a N-terminal pyroglutamic acid preceded by a signal peptide of 20 amino acid residues. The amino acid sequence of ARP was 99% identical to that of the peroxidase of Coprinus cinereus, a basidiomycete, and also had very high similarities (41-43% identity) to those of basidiomycetous lignin peroxidases, although we could find no lignin peroxidase activities for ARP when assayed with lignin model compounds. We could identified His184 and His56 as proximal and distal ligands to heme, respectively, and Arg52 as an essential Arg. Comparison of the sequences of complementary and genomic DNAs found that protein-encoding DNA is interrupted by 14 intervening sequences. The ARP cDNA was expressed in the yeast Saccharomyces cerevisiae under the promoter of the glyceraldehyde 3-phosphate dehydrogenase gene, yielding 0.02 units/ml of a secreted active peroxidase.
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PMID:Cloning, sequencing, and heterologous expression of a gene coding for Arthromyces ramosus peroxidase. 767 Jan 82

The promoter region of the glyceraldehyde-3-phosphate dehydrogenase gene (gpd) was used to drive expression of mnp1, the gene encoding Mn peroxidase isozyme 1, in primary metabolic cultures of Phanerochaete chrysosporium. A 1,100-bp fragment of the P. chrysosporium gpd promoter region was fused upstream of the mnp1 gene to construct plasmid pAGM1, which contained the Schizophyllum commune ade5 gene as a selectable marker. pAGM1 was used to transform a P. chrysosporium ade1 auxotroph to prototrophy. Ade+ transformants were screened for peroxidase activity on a solid medium containing high carbon and high nitrogen (2% glucose and 24 mM NH4 tartrate) and o-anisidine as the peroxidase substrate. Several transformants that expressed high peroxidase activities were purified and analyzed further in liquid cultures. Recombinant Mn peroxidase (rMnP) was expressed and secreted by transformant cultures on day 2 under primary metabolic growth conditions (high carbon and high nitrogen), whereas endogenous wild-type mnp genes were not expressed under these conditions. Expression of rMnP was not influenced by the level of Mn in the culture medium, as previously observed for the wild-type Mn peroxidase (wtMnP). The amount of active rMnP expressed and secreted in this system was comparable to the amount of enzyme expressed by the wild-type strain under ligninolytic conditions. rMnP was purified to homogeneity by using DEAE-Sepharose chromatography, Blue Agarose chromatography, and Mono Q column chromatography. The M(r) and absorption spectrum of rMnP were essentially identical to the M(r) and absorption spectrum of wtMnP, indicating that heme insertion, folding, and secretion were normal.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Homologous expression of recombinant manganese peroxidase in Phanerochaete chrysosporium. 781 Oct 70

Vanadate forms a stable complex with H2O2 at pH 7.0 in competition with catalase and the product, diperoxovanadate, resists scavenger action of catalase. Diperoxovanadate can act as a substrate in a H2O2-user reaction, horseradish peroxidase and can take the place of H2O2 far more effectively in oxidatively inactivating glyceraldehyde-3-phosphate dehydrogenase. By forming peroxo-complexes vanadate can provide a way of preserving cellular H2O2 in presence of abundant catalase and make it available for its functions.
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PMID:Diperoxovanadate participates in peroxidation reactions of H2O2 in presence of abundant catalase. 968 67

Replacing the essential Cys-149 by a selenocysteine into the active site of phosphorylating glyceraldehyde 3-phosphate dehydrogenase (GAPDH) from Bacillus stearothermophilus leads to a selenoGAPDH that mimics a selenoperoxidase activity. Saturation kinetics were observed with cumenyl and tert-butyl hydroperoxides, with a better catalytic efficiency for the aromatic compound. The enzymatic mechanism fits a sequential model where the formation of a ternary complex between the holoselenoenzyme, the 3-carboxy 4-nitrobenzenethiol used as the reductant and the hydroperoxide precedes product release. The fact that the selenoGAPDH is NAD-saturated supports a binding of hydroperoxide and reductant in the substrate binding site. The catalytic efficiency is similar to selenosubtilisins but remains low compared to selenoglutathione peroxidase. This is discussed in relation to what is known from the X-ray crystal structures of selenoglutathione peroxidase and GAPDHs.
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PMID:Substituting selenocysteine for active site cysteine 149 of phosphorylating glyceraldehyde 3-phosphate dehydrogenase reveals a peroxidase activity. 984 30

The glyceraldehyde-3-phosphate dehydrogenase (gpd) promoter was used to drive expression of lip2, the gene encoding lignin peroxidase (LiP) isozyme H8, in primary metabolic cultures of Phanerochaete chrysosporium. The expression vector, pUGL, also contained the Schizophyllum commune ura1 gene as a selectable marker. pUGL was used to transform a P. chrysosporium Ura11 auxotroph to prototrophy. Ura+ transformants were screened for peroxidase activity in liquid cultures containing high-carbon and high-nitrogen medium. Recombinant LiP (rLiP) was secreted in active form by the transformants after 4 days of growth, whereas endogenous lip genes were not expressed under these conditions. Approximately 2 mg of homogeneous rLiP/liter was obtained after purification. The molecular mass, pI, and optical absorption spectrum of rLiPH8 were essentially identical to those of the wild-type LiPh8 (wt LiPH8), indicating that heme insertion, folding, and secretion functioned normally in the transformant. Steady-state and transient-state kinetic properties for the oxidation of veratryl alcohol between wtLiPH8 and rLiPH8 were also identical.
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PMID:Homologous expression of recombinant lignin peroxidase in Phanerochaete chrysosporium. 1010 66

We investigated the effect of sublethal concentrations of hypochlorous acid (HOCl) on intracellular thiol groups. Exposure of human umbilical vein endothelial cells to HOCl caused a decrease in cell viability, with concentrations of </=25 microM HOCl being sublethal. At these concentrations, we saw a loss of glutathione and total protein thiol groups. Of the thiol enzymes we investigated, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was particularly susceptible to inactivation, creatine kinase was moderately susceptible, and lactate dehydrogenase was unaffected by HOCl at the concentrations used. Similar results were obtained with HOCl generated over 30 min by myeloperoxidase. GAPDH activity could be regenerated on reincubation of cells in Hanks' balanced salt solution or reduction with dithiothreitol. In contrast, glutathione loss was not reversible, and further decreased with time. Cellular ATP levels decreased with sublethal HOCl concentrations and this appeared to be unrelated to the inactivation of GAPDH. Our results demonstrate that intracellular thiol groups differ in their reactivity with HOCl and suggest that HOCl may be able to regulate specific cellular functions.
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PMID:Loss of GSH and thiol enzymes in endothelial cells exposed to sublethal concentrations of hypochlorous acid. 1051 89


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