Comparison of the catalytic oxidation of cysteine and o-dianisidine by cupric ion and ceruloplasmin

Feldman, Stuart; Hunter, James S.; Zgirski, Alojzy; Chidambaram, M. V.; Frieden, Earl

doi:10.1016/s0162-0134(00)80229-9

Cited by 23 publications

(7 citation statements)

References 5 publications

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“…In addition, it can function as an antioxidant (27) and as a scavenger of the superoxide anion radical (14). Recent work has also suggested that Cp may catalyze the oxidation of various thiol-containing molecules with the release of a variety of oxygen radicals (28)(29)(30). The data presented here indicate that Cp can also augment the inhibitory effect of D-penicillamine on T cell function as effectively as CuS04 by promoting the generation of H202.…”

Section: Discussionmentioning

confidence: 58%

“…However, previous investigators have shown that cupric ions or Cp have the capacity to oxidize thiol compounds with the production of superoxide anions and H202. Some controversy exists concerning whether D-penicillamine is an appropriate substrate for this reaction (28)(29)(30). However, in the current studies it is clear that the mixture of D-penicillamine and Cp at the concentrations used and with the incubation medium used is capable of generating adequate H202 to cause T cell toxicity.…”

Section: Discussionmentioning

confidence: 84%

See 1 more Smart Citation

Immunosuppression by D-penicillamine in vitro. Inhibition of human T lymphocyte proliferation by copper- or ceruloplasmin-dependent generation of hydrogen peroxide and protection by monocytes.

Lipsky¹

1984

J. Clin. Invest.

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It has been suggested that D-penicillamine is active in rheumatoid arthritis because of its capacity to function as a selective inhibitor of T lymphocyte function. The basis for the immunosuppressive action of this drug as well as mechanisms whereby the effect of D-penicillamine could be modified by elements of rheumatoid synovial tissue were examined. As previously reported, D-penicillamine, in the presence of copper ions markedly inhibited mitogen-induced human T lymphocyte DNA synthesis. Since the vast majority of copper in the body exists as an integral part of the ceruloplasmin molecule, the capacity of this cuproprotein to augment D-penicillamine-mediated inhibition of T cell function was examined. The requirement for copper ions could be entirely replaced by purified ceruloplasmin, which had been depleted of nonspecifically bound copper by passage over Chelex-100 columns. The mechanism by which D-penicillamine in the presence of either copper ions or ceruloplasmin caused inhibition of T lymphocyte responsiveness was examined. Partial protection from this inhibitory effect was accomplished by sodium borohydride. While superoxide dismutase had no protective effect, catalase was found to protect lymphocyte responsiveness totally from the inhibitory action of D-penicillamine and either copper ions or ceruloplasmin. Similarly, horseradish peroxidase and myeloperoxidase also protected responsiveness from these inhibitors while boiled catalase was without effect. These results indicate that inhibition of T lymphocyte responsiveness resulted from the generation of hydrogen peroxide. Since a number of cells likely to be present at chronic inflammatory sites, such as mononuclear phagocytes, contain enzymatic mechanisms to degrade hydrogen peroxide, the modulatory influence of these cells on the inhibition of T cell function caused by D-penicillamine and copper was examined. Monocytes, whose function was not suppressed by D-penicillamine and copper, were found to protect T lymphocyte responsiveness from the inhibitory effects of either the mixture of D-penicillamine and CuSO4 or of hydrogen peroxide. By contrast, endothelial cells, fibroblasts, or cells obtained from enzyme-digested noninflamed synovium could not protect T cells from the inhibitory effects of D-penicillamine and copper. Protection of T cells was afforded by means of a heat labile, azide-sensitive soluble factor present in lysates of human monocytes. These results indicate that the mechanism whereby D-penicillamine in the presence of copper or ceruloplasmin inhibits T lymphocyte responsiveness involves the generation of hydrogen peroxide and that other neighboring cells likely to be found w

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Section: Discussionmentioning

confidence: 58%

Section: Discussionmentioning

confidence: 84%

Immunosuppression by D-penicillamine in vitro. Inhibition of human T lymphocyte proliferation by copper- or ceruloplasmin-dependent generation of hydrogen peroxide and protection by monocytes.

Lipsky¹

1984

J. Clin. Invest.

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“…4A). The addition of L-cysteine, which is oxidized by copper (23), to plates along with CuSO 4 blocked activation of the Cpx pathway (Fig. 4A).…”

Section: Resultsmentioning

confidence: 97%

Genetic Analysis of Activation of the Vibrio cholerae Cpx Pathway

Slamti

Waldor

2009

J Bacteriol

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The Cpx two-component system is thought to mediate envelope stress responses in many gram-negative bacteria and has been implicated in the pathogenicity of several enteric pathogens. While cues that activate the Escherichia coli Cpx system have been identified, the nature of the molecular signals that stimulate this pathway is not well understood. Here, we investigated stimuli that trigger this system in Vibrio cholerae, a facultative pathogen that adapts to various niches during its life cycle. In contrast to E. coli, there was no basal activity of the V. cholerae Cpx pathway under standard laboratory conditions. Furthermore, several known stimuli of the E. coli pathway did not induce expression of this system in V. cholerae. There were no defects in intestinal growth in V. cholerae cpx mutants, arguing against the idea that this pathway promotes V. cholerae adaptation to conditions in the mammalian host. We discovered that chloride ions activate the V. cholerae Cpx pathway, raising the possibility that this signal transduction system provides a means for V. cholerae to sense and respond to alterations in salinity. We used a genetic approach to screen for mutants in which the Cpx pathway is activated. We found that mutations in genes whose products are required for periplasmic disulfide bond isomerization result in activation of the Cpx pathway, suggesting that periplasmic accumulation of proteins with aberrant disulfide bonds triggers the V. cholerae Cpx pathway.

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“…MCO activity was determined by using 3,3Ј-dimethoxybenzidine as described earlier (5,15,18). This enzymatic activity was copper dependent, and the presence of 0.5 mM CuSO 4 is optimum for enzymatic activity.…”

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confidence: 99%

Characterization of a Multicopper Oxidase Gene from Staphylococcus aureus

Sitthisak

Howieson

Amezola

et al. 2005

Appl Environ Microbiol

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A multicopper oxidase gene from Staphylococcus aureus was cloned and overexpressed. Purified recombinant multicopper oxidase oxidized the substrate 3,3-dimethoxybenzidine in the presence of copper. Disruption of mco showed copper sensitivity and H 2 O 2 resistance, suggesting roles for mco in copper homeostasis and oxidative stress response. Northern blot analysis showed copper-induced mco transcription.Multicopper oxidases (MCO) are enzymes that are critically involved in copper homeostasis. These enzymes show enhanced oxidase activity for a wide range of substrates (1,2,4,9,22,24) and play a role in iron transport in eukaryotes and prokaryotes (9,23). mco genes have been cloned and identified from animals, plants, insects, fungi, and bacteria (3,4,8,12,16). However, there is no report of mco in Staphylococcus aureus.We have been investigating the regulation of metal transport and homeostasis in S. aureus (25,26). To identify new loci involved in metal homeostasis in S. aureus, we selected streptonigrin-resistant clones from a transposon Tn917-induced mutant library of S. aureus strain ATCC 12600 and characterized mutants by cloning and sequencing. In this study, we identified one of the mutations in the gene encoding multicopper oxidase.Staphylococcus aureus strains were grown in tryptic soy broth (TSB) or defined medium. Escherichia coli strains were grown in Luria-Bertani broth with the appropriate antibiotic. DNA manipulation, sequencing, cloning, transformation, and overexpression were performed as described earlier (7,21,26). DNA sequences were determined with an ABI Prism 310 automated sequencer (Perkin Elmer, Foster City, CA).The Tn917-flanking sequence of the mutant was cloned in E. coli as described earlier (21). Nucleotide analysis of the flanking region of the Tn917 insertion of one of the streptonigrinresistant clones showed sequence homology to putative multicopper oxidases. The complete nucleotide sequence of the parental gene copy of S. aureus showed an open reading frame (ORF) comprising 1,389 bp encoding a hypothetical polypeptide of 462 amino acids with a predicted molecular mass of 52 kDa and pI of 9.68. Nucleotide comparison showed a 99% sequence identity with a gene in the S. aureus EMRSA-16 database. Amino acid comparisons of the translated ORF showed 84% identity to putative MCO from Staphylococcus epidermidis and 26 to 41% identities to laccase, CueO, and ascorbate oxidase, which are members of the MCO family. Therefore, we designated this ORF mco. Seventy nucleotides upstream of mco, an ORF designated copA, a copper ATPase, was also identified (Fig. 1).The multicopper oxidase gene from S. aureus was cloned and overexpressed in E. coli BL21(DE3). MCO activity was determined by using 3,3Ј-dimethoxybenzidine as described earlier (5,15,18). This enzymatic activity was copper dependent, and the presence of 0.5 mM CuSO 4 is optimum for enzymatic activity. The purified MCO showed a specific activity of 9.7 U/mg, compared to 1.6 U/mg in the crude extract (Table 1). The purified MCO also exhibi...

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Comparison of the catalytic oxidation of cysteine and o-dianisidine by cupric ion and ceruloplasmin

Cited by 23 publications

References 5 publications

Immunosuppression by D-penicillamine in vitro. Inhibition of human T lymphocyte proliferation by copper- or ceruloplasmin-dependent generation of hydrogen peroxide and protection by monocytes.

Immunosuppression by D-penicillamine in vitro. Inhibition of human T lymphocyte proliferation by copper- or ceruloplasmin-dependent generation of hydrogen peroxide and protection by monocytes.

Genetic Analysis of Activation of the Vibrio cholerae Cpx Pathway

Characterization of a Multicopper Oxidase Gene from Staphylococcus aureus

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