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)

Porphyromonas gingivalis (Bacteroides gingivalis) requires iron in the form of hemin for growth and virulence in vitro, but the contributions of the porphyrin ring structure, porphyrin-associated iron, host hemin-sequestering molecules, and host iron-withholding proteins to its survival are unknown. Therefore, the effects of various porphyrins, host iron transport proteins, and inorganic iron sources on the growth of P. gingivalis W50 were examined to delineate the various types of iron molecules used for cellular metabolism. Cell envelope-associated hemin and iron stores contributed to the growth of P. gingivalis in hemin-free culture, and depletion of these endogenous reserves required eight serial transfers into hemin-free medium for total suppression of growth. Comparable growth of P. gingivalis was observed with 7.7 microM equivalents of hemin as hemoglobin (HGB), methemoglobin, myoglobin, hemin-saturated serum albumin, lactoperoxidase, cytochrome c, and catalase. Unrestricted growth was recorded in the presence of haptoglobin-HGB and hemopexin-hemin complexes, indicating that these host defense proteins do not sequester HGB and hemin from P. gingivalis. The iron chelator 2,2'-bipyridyl functionally chelated hemin-associated iron, resulting in dose-dependent inhibition of growth in hemin-restricted cultures at 1 to 25 microM 2,2'-bipyridyl concentrations. In the absence of an exogenous iron source, protoporphyrin IX did not support P. gingivalis growth. These findings suggest that the iron atom in the hemin molecule is the critical constituent for growth and that the tetrapyrrole porphyrin ring structure may represent an important vehicle for delivery of iron into the P. gingivalis cell. P. gingivalis does not have a strict requirement for porphyrins, since growth occurred with nonhemin iron sources, including high concentrations (200 muM) of ferric, ferrous, and nitrogenous inorganic iron, and P. gingivalis exhibited unrestricted growth in the presence of host transferrin, lactoferrin, and serum albumin. The diversity of iron substrates utilized by P. gingivalis and the observation that growth was not affected by the bacteriostatic effects of host iron-withholding proteins, which it may encounter in the periodontal pocket, may explain why P. gingivalis is such a formidable pathogen in the periodontal disease process.
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PMID:Roles of porphyrins and host iron transport proteins in regulation of growth of Porphyromonas gingivalis W50. 165 88

Components involved in superoxide anion production (cytochrome b) and in cell adhesion processes (CD11b, CD11c, CD18), two early functional responses of neutrophils during acute inflammation, are intracellularly located in resting human neutrophils. We have found a correlation between secretion of gelatinase and overexpression in the plasma membrane of CD11b, CD11c, CD18 and cytochrome b upon cell activation. Gelatinase and lactoferrin were parallely released after cell activation with different stimuli, but a better correlation between antigen up-regulation and gelatinase release was obtained. Total translocation of the intracellular pool of these mobilizable molecules to plasma membrane was achieved under conditions that induced total degranulation of the gelatinase-rich granule population, whereas 50% and 90% of the lactoferrin-containing secondary granules and peroxidase-containing primary granules, respectively, remained unfused. These results suggest a mechanism by which neutrophil function can be regulated through mobilization of gelatinase-rich granules, which can be considered as a subpopulation of secondary granules.
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PMID:Mobilization of gelatinase-rich granules as a regulatory mechanism of early functional responses in human neutrophils. 167 56

Our previous skin chamber studies have shown prominent accumulation of viable neutrophils in human allergic skin reaction sites. To determine whether such neutrophils release components that may be pathogenic in allergic reactions, we have compared the patterns of release of five components: 1) lactoferrin, present in specific granules; 2) and 3) elastase and myeloperoxidase, present mainly in azurophilic granules; 4) lactic dehydrogenase, a cytosolic component generally released during cell damage; 5) histamine, present in mast cells and basophils but not in neutrophils. In 13 pollen-sensitive subjects we found that continuous antigen challenge for 5 h lead to a peak of histamine release into overlying skin chambers during the 1st h, followed by a plateau of low level histamine release over the succeeding 4 h. In contrast, there was no significantly increased released of lactoferrin or elastase during the first h, but significantly increased accumulation of these components at Ag challenge sites over the next 4 h. There was no significant difference at Ag vs buffer control sites in the levels of either myeloperoxidase or lactic dehydrogenase. The increased levels of lactoferrin and elastase at antigen challenge sites in the 2nd to 5th h were not simply a reflection of the greater numbers of neutrophils present in such sites because the levels of these components did not correlate significantly with the number of neutrophils in chamber fluids obtained from individual sites. However, such lactoferrin levels did correlate significantly with the amount of histamine released earlier during the 1st h of Ag challenge at individual sites. These findings suggest a selective in vivo release of neutrophil components in IgE-mediated human allergic skin reactions, possibly related in degree to earlier mast cell activation. Inasmuch as lactoferrin likely plays a role in reactive oxidants effects and elastase is a potent nonspecific protease, release of these agents could play a pathogenic role in late phase allergic reactions.
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PMID:Release of lactoferrin and elastase in human allergic skin reactions. 169 68

Lactoferrin (LF) and myeloperoxidase (MPO) are glycoproteins synthesized in early myeloid cells (promyelocytes, myelocytes) and stored in granules of polymorphonuclear neutrophilic granulocytes. Both proteins are involved in the host inflammatory response, and LF has been found to have myelosuppressive activity in vivo and in vitro. Little is known, however, about the regulation of their production. We investigated the stability of LF and MPO mRNA and the effects of purified recombinant human TNF-alpha on LF and MPO levels in normal human bone marrow. Low density human bone marrow cells were cultured in the presence or absence of actinomycin D (10 micrograms/ml) or TNF-alpha (200 U/ml). LF and MPO RNA levels were analyzed by Northern blots using, respectively, a 650-bp insert from the plasmid pHL41, and a 2.3-kb insert from the plasmid pMPO2 as probes. It was found that: 1) LF mRNA is a fairly stable molecule, with a half-life of between 8 and 9 h, whereas MPO is less stable, with a half-life of between 4 and 5 h; 2) TNF-alpha decreases both LF and MPO mRNA levels, an effect seen by 24 h with MPO mRNA and 48 h with LF mRNA; 3) nuclear run-on assays revealed that TNF decreases transcription of the LF gene by 70% and the MPO gene by 50%; and 4) the suppressive effect of TNF-alpha on LF and MPO mRNA levels is not due to cell killing or selective differentiation and is reversible.
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PMID:Regulation of human bone marrow lactoferrin and myeloperoxidase gene expression by tumor necrosis factor-alpha. 170 77

The local, saliva-associated defense mechanisms of 28 juvenile periodontitis (JP) patients and their age- and sex-matched controls were studied. Lysozyme, lactoferrin, salivary peroxidase, myeloperoxidase, and thiocyanate concentrations were determined from both whole saliva and parotid saliva. The total concentrations of salivary IgA, IgG, and IgM were assayed. The periodontal condition and the salivary flow rates were registered. Among the JP patients, a significantly elevated concentration of IgG was found in parotid saliva but not in whole saliva. Salivary peroxidase activities were significantly low both in the whole and in the parotid saliva samples of the JP patients, and leukocyte-derived myeloperoxidase was present in significantly low amounts in whole saliva of these patients. Because both glandular (salivary peroxidase) and polymorphonuclear-cell-derived (myeloperoxidase) enzyme activities were low among the JP patients, suppressed peroxidase-mediated host defense mechanisms could be characteristic of JP.
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PMID:Salivary defense mechanisms in juvenile periodontitis. 170 74

The results presented during the Third International ANCA Workshop, Washington, DC, 1990, allowed a better definition of the antigenic specificity of the antineutrophil cytoplasmic autoantibodies (ANCA). The large predominance of two major antigen specificities for proteinase 3 (PR3) and myeloperoxidase (MPO), in the group of vasculitic patients, was confirmed. PR3 and MPO are colocalized in the azurophilic granules of neutrophils and translocated to the cell surface during activation and thus are able to interact with ANCA after neutrophil preactivation. Furthermore, by comparison of amino acid and DNA sequences, the agreement was reached that PR3 was identical to AGP7, p29, and myeloblastin, described independently and involved in the control of growth and differentiation of leukemic cells. In addition to the two major ANCA antigens, a number of neutrophil cytoplasmic antigens recognized by ANCA have been previously identified (human leukocyte elastase [HLE], lactoferrin). It was established during the Third Workshop that these rare ANCA specificities, occurring in a limited number of patients, include a cationic antimicrobial protein (CAP57) and cathepsin G. However, the variety of ANCA antigen specificities contrasts with the fact that the vast majority of ANCA-positive sera are monospecific for a single ANCA antigen. Finally, the fine specificity of granulocyte-specific antinuclear antibodies (GS-ANA) occurring in rheumatoid arthritis and ulcerative colitis is still unknown, but clearly a substantial proportion of GS-ANA belongs to the ANCA family.
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PMID:Antineutrophil cytoplasmic autoantibodies antigen specificity. 171 31

The transcriptional regulation of myeloperoxidase (MPO) and lactoferrin (LF) was examined during terminal myeloid differentiation of the murine cell line 32D C13. The rates of transcription initiation for MPO and LF, determined by an in vitro nuclear run-on assay, increased approximately ninefold. The accumulation of MPO mRNA in 32D C13 cells, determined by Northern blot analysis, correlated temporally with the observed increase in MPO transcription initiation. On the other hand, accumulation of LF mRNA lagged behind the observed increase in LF transcription initiation. In mouse L cells, the LF gene was transcribed more frequently than the MPO gene, though neither mRNA accumulated. Finally, murine MPO transcription is shown, by Northern blot and primer extension analysis, to initiate at multiple sites. These results indicate that whereas transcription induction may largely account for the accumulation of MPO mRNA during terminal myeloid differentiation, both transcriptional and posttranscriptional mechanisms operate to allow accumulation of LF mRNA. The 32D C13 cell system will be a useful model for elucidating these mechanisms.
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PMID:Transcriptional regulation of two myeloid-specific genes, myeloperoxidase and lactoferrin, during differentiation of the murine cell line 32D C13. 171 97

The antigenic specificity and clinical distribution of the antineutrophil cytoplasmic antibodies (ANCA) in kidney diseases have recently been extensively studied. In patients with systemic vasculitis, the great predominance of two major ANCA antigens, proteinase 3 (PR3) and myeloperoxidase (MPO), is now established. PR3 and MPO are colocalized in the azurophilic granules of neutrophils and translocated to the cell surface during activation, and thus are able to interact with autoantibodies after neutrophil preactivation. Furthermore, by comparison of amino acid and DNA sequences, it has been shown that PR3 is identical to myeloblastin, which has been described independently and is involved in the control of growth and differentiation of leukemic cells. Aside from the two major ANCA antigens, a number of neutrophil cytoplasmic antigens recognized by ANCA have been identified, including human leukocyte elastase, lactoferrin, CAP57, and cathepsin G. These rare ANCA specificities occur in a limited number of patients. The variety of ANCA antigen specificities contrasts, however, with the fact that the vast majority of ANCA-positive sera are monospecific for one single ANCA antigen. With regard to clinical distribution, ANCA have major diagnostic significance in the four conditions in which they are frequently detected: Wegener's granulomatosis (WG), Churg and Strauss Syndrome (CSS), microscopic periarteritis (MPA), and necrotic and crescentic glomerulonephritis (NCGN). However, the initial dichotomy between MPO-associated vasculitis (NCGN, MPA) and that associated with anti-PR3 antibodies (WG) appears far from absolute.
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PMID:Antigen specificities and clinical distribution of ANCA in kidney diseases. 172 65

The relationship between histological type and immunohistological findings was studied in total 141 cases of resected lung cancer. Adenocarcinoma was cytologically subtyped according to the ultrastructural findings. Immunohistochemical staining was performed on paraffin-embedding tissue using the avidin-biotin-peroxidase complex method for carcinoembryonic antigen (CEA), keratin, secretory component (SC), neuron specific enolase (NSE), lysozyme (Ly) and lactoferrin (La). Adenocarcinoma stained strongly positive with antibody against CEA and SC. There was no statistical difference among the different subtypes of adenocarcinoma, but in the cases of clara cell type, CEA staining was less intense and in goblet cell type, the intensity of SC staining was great. Goblet cell type characteristically stained positively with anti-Ly antibody, and Ly was a specific marker for differentiating adenocarcinoma of goblet cell type. La was positive not only in bronchial gland cell type, but also in other subtypes in adenocarcinoma. Squamous cell carcinoma showed more intense staining with anti-keratin antibody than other histological types. Small cell carcinoma extensively stained with anti-NSE antibody, but some of the other histological types also stained positively. NSE was a relatively good marker for small cell carcinoma but was not specific. It is concluded that immunohistochemical examination is a useful method for differentiation of different histological types of lung cancer.
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PMID:[Immunohistochemical findings in resected lung cancer]. 175 99

We have studied the effects of iron-free lactoferrin (apo LF) and lactoperoxidase system (lactoperoxidase, LP/SCN-/H2O2), separately and together, on the viability of Streptococcus mutans (serotype c) in vitro. The bacteria were incubated in buffered KCl (pH 5.5) with and without the above components which were used at concentrations normally present in human saliva. Both apo LF and LP-system had a bactericidal effect against S. mutans at low pH. Together they showed an additive, but not a synergistic, antibacterial effect against S. mutans. Apo LF enhanced the LP enzyme activity but decreased the yield of the antimicrobial component, hypothiocyanite (HOSCN/OSCN-), when incorporated into the reaction mixtures. This decrease, which was most pronounced at low pH, was due to an LP-independent reaction between apo LF and HOSCN/OSCN-. Our study indicates that the LP-system and apo LF can be combined to combat oral S. mutans.
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PMID:Combined inhibitory effect of lactoferrin and lactoperoxidase system on the viability of Streptococcus mutans, serotype c. 175 41


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