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)

Extracts of specific granules and azurophil granules from human neutrophils were tested for their bactericidal activity against various lipopolysaccharide mutants of Salmonella typhimurium LT-2. Three purified granule populations, one specific and two azurophil, were obtained by isopycnic centrifugation of homogenized neutrophils. Each was extracted with 0.2 M acetate buffer (pH 4), and the extracts were dialyzed against phosphate-buffered saline (pH 7) to remove acetate. These extracts contained >/=84% of the lysozyme, lactoferrin, or myeloperoxidase initially present in the whole granules. The S. typhimurium mutants possessed Ra, Rc, Rd(1), Rd(2), or Re lipopolysaccharide. As the carbohydrate content of the lipopolysaccharide decreased, the bacteria became increasingly more susceptible to the bactericidal activity of all granule extracts. Bactericidal activity of the extracts was in the order: mixed (azurophil + specific) >/= azurophil >> specific. Specific granules were bacteriostatic for S through Rd(2) bacteria. They were bactericidal only for the Re mutant. Both azurophil granule populations were equally bactericidal. Extracts boiled for 30 min retained none of their bactericidal activity for any of the bacteria; however, they remained bacteriostatic for the deep rough (Rd(2), Re) mutants. Bactericidal activity was dependent upon pH, in that mixed and azurophil granule contents killed the smooth parent and Ra mutant best at pH 5, the Rc and Rd(1) mutants to the same degree at pH 5 to 8, and the deep rough mutants (Rd(2) and Re) best at pH 8. Specific granule contents were most bacteriostatic for S through Rd(2) bacteria at pH 5 and killed the Re mutant only at pH 8. Thus, as the S. typhimurium lipopolysaccharide content decreased, the bactericidal pH optimum increased. Killing by all extracts was dependent upon incubation temperature, with almost no bactericidal or bacteriostatic activity observed when bacteria and granule fractions were incubated on ice (2 degrees C) and plated immediately. Intermediate killing was observed at 22 degrees C. If bacteria were incubated with granule extracts at 2 degrees C, washed free of extract, suspended in medium without extract, and reincubated at 37 degrees C, killing was observed. This suggested that a component(s) of the extracts was sticking to the bacteria at 2 degrees C but killing only at 37 degrees C.
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PMID:Bactericidal activity of specific and azurophil granules from human neutrophils: studies with outer-membrane mutants of Salmonella typhimurium LT-2. 2

The subcellular distribution of nine glycosidases were studied in fractions of homogenized human polymorphonuclear leucocytes (neutrophils) obtained by isopycnic centrifugation through linear sucrose density gradients. The substrates were 4-methylumbelliferyl glycosides. All nine glycosides were hydrolysed by enzymes in neutrophil cytosol fractions, and by enzymes in at least one granule population. alpha-Glucosidase activity sedimented in sucrose density gradients to a point (p = 1.180 g/ml) just above the specific granules, possibly the 'tertiary' granule population. The peak corresponding to alpha-glucosidase did not co-sediment with, but considerably overlapped, the peak corresponding to lactoferrin, a marker for specific granules (p = 1.187 g/ml). alpha-Galactosidase activity was found primarily in heavy azurophil granules (p = 1.222 g/ml). alpha-Mannosidase activity was found primarily in light azurophil granules (p = 1.206 g/ml), following the distribution of myeloperoxidase, the commonly used azurophil granule marker. beta-Glucosidase activity was concentrated in mitochondrial fractions (p = 1.160 g/ml). All other glycosidases presented complex distributions, with activities not restricted to one granule class. Granule-associated glycosidase activities were increased 2--38 times when measured in the presence of 0.05% Triton X-100, indicating latency of the enzymes within granules.
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PMID:Subcellular distribution of glycosidases in human polymorphonuclear leucocytes. 2 8

We used immunofluorescent microscopy to characterize the abnormal granules in neutrophils from five patients with Chediak-Higashi disease. Monospecific antiserums to the azurophilic markers myeloperoxidase, elastase, cathepsin G and lysozyme, and to the specific granule markers lactoferrin and lysozyme, were labeled with fluorescein and rhodamine and were used to demonstrate two antigens in the same cell simultaneously. The abnormal granules in Chediak-Higashi neutrophils contained both azurophilic and specific granule markers. Normal-appearing lactoferrin-positive granules were also present, but normal azurophilic granules were not seen. Analysis of bone-marrow samples from two of these patients suggested that the abnormal granules were formed during granulocyte maturation by the progressive aggregation and fusion of normally formed azurophilic and specific granules. These results are consistent with a membrane abnormality or a defect of microtubular function leading to inappropriate granule fusion, and suggest that the granular abnormality is more generalized than previously appreciated.
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PMID:Immunocytochemical identification of azurophilic and specific granule markers in the giant granules of Chediak-Higashi neutrophils. 7 4

The use of alkaline phosphatase in an immunoenzymatic procedure for the localisation of antigens in paraffin sections or cell smears is described. The results of this method, when applied to the detection of immunoglobulins, lysozyme, or lactoferrin, were comparable in intensity and clarity to those obtained with the PAP immunoperoxidase procedure. Furthermore, double immunoenzymatic labelling (with alkaline phosphatase and peroxidase) of two cellular constituents in a tissue section is possible, the brown peroxidase reaction product contrasting well with the blue alkaline phosphatase product. Since the two antibody 'sandwiches' are applied simultaneously rather than sequentially the total duration of this double immunostaining procedure is only a few minutes longer than that required for detection of a single antigen. It was also found that the unlabelled antibody immunohistological procedure (whether used in conjunction with alkaline phosphatase or peroxidase) can be shortened without loss of sensitivity by carrying out two of the incubation steps simultaneously.
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PMID:Alkaline phosphatase and peroxidase for double immunoenzymatic labelling of cellular constituents. 7 79

Gonococci are capable of attaching to the surface of polymorphonuclear leukocytes (PMN). In this location they resist phagocytosis and are not killed by PMN. To delineate the factors involved in the survival of these gonococci, we investigated the interaction of virulent gonococci, which adhere to cells and resist phagocytosis, and avirulent gonococci, which are phagocytized and killed by PMN. In the presence of serum, both virulent and avirulent gonococci associate equally well with PMN and stimulate increases in oxidative metabolism. In the absence of serum virulent gonococci attached to PMN and stimulated PMN oxidative metabolism to a greater extent than avirulent gonococci which did not attach to PMN (P = 0.0009). Therefore, the survival of virulent gonococci attached to the PMN surface is not a result of failure to activate oxidative and bactericidal mechanisms. Both virulent and avirulent gonococci stimulated equivalent PMN specific granule release as measured by the appearance of lactoferrin in the media. Phagocytosis of avirulent gonococci stimulated significantly greater beta-glucuronidase release (P = 0.01) and myeloperoxidase-mediated iodination of protein (P = 0.001) by PMN than attachment of virulent gonococci. In the absence of serum neither type of gonococci stimulated beta-glocuronidase release or protein iodination by PMN. Thus, virulent gonococci fail to stimulate primary granule release by PMN. To further assess the role of attachment versus ingestion on the survival of gonococci, PMN were treated with cytochalasin B to block ingestion. Cytochalasin B-treated PMN were unable to kill either virulent or avirulent gonococci despite normal degranulation stimulated by the latter. The failure of PMN to kill surface-attached gonococci appears to be a consequence of the failure of PMN to enclose the virulent gonococci within a phagosome. The phagocytic vacuole thus plays a critical role in normal PMN bactericidal activity by providing a closed space in which the proper concentration of substances may be achieved to generate microbicidal activity.
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PMID:Gonococcal interactions with polymorphonuclear neutrophils: importance of the phagosome for bactericidal activity. 10 96

In 31 patients, covering a wide range of blood neutrophil counts and turnover rates, the plasma concentrations of myeloperoxidase and lactoferrin have been measured with radioimmunoassays and compared to neutrophil kinetic parameters, measured with DF32P-labeled neutrophils. It was found that the plasma concentrations of both proteins correlated significantly with the total number of neutrophils in the blood (TBGP=total blood granulocyte pool) as well as with the neutrophil turnover rate (GTR=granulocyte turnover rate), which is evidence that neutrophilic granulocytes are the main suppliers of myeloperoxidase and lactoferrin to the plasma. In contrast to the previously demonstrated better relationship between the GTR and plasma lysozyme, a protein also originating in neutrophil granules, both myeloperoxidase and lactoferrin correlated better with the TBGP. These differences may reflect differences in the mode of release of intragranular proteins from neutrophils to the plasma. The correlation of the plasma lactoferrin concentration with the TBGP was so good as to suggest its use in the clinical assessment of the TBGP.
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PMID:Plasma myeloperoxidase and lactoferrin measured by radioimmunoassay: relations to neutrophil kinetics. 17 93

The changes in intraneutrophilic and plasma concentrations of the three antibacterial proteins lysozyme, lactoferrin, and myeloperoxidase were studied sequentially during acute bacterial infection in nine patients. Intraneutrophilic concentrations of the three proteins were decreased by more than 50% during the 1st week of infection, followed by a slow increase over the following 2 weeks. Nadir values coincided with maximal toxic granulation of the neutrophils. The data suggest that neutrophilic granulocytes are deficient during early bacterial infection, possibly because of deficient synthesis of antibacterial proteins in the bone marrow, and that neutrophil toxic granulation is the visual counterpart of this defect. The plasma concentrations of the three proteins showed considerable differences: whereas plasma lysozyme did not show any sequential changes, plasma myeloperoxidase was high at the start of infection and quickly decreased towards normal values, and plasma lactoferrin, high in the first samples, showed a secondary peak 1 week after onset of disease, before normalization was seen. These differences may result from differences in the signals are specific for the individual antibacterial protein and not for the different types of neutrophil granules.
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PMID:Neutrophilic granulocytes in acute bacterial infection. Sequential studies on lysozyme, myeloperoxidase and lactoferrin. 18 78

Radioimmunosorbent assays for determination of serum content of the neutrophil proteins myeloperoxidase and lactoferrin are described. Serial studies were performed in patients with neutropenia. In 2 cases of cyclic neutropenia the myeloperoxidase level showed slight variations within the normal range during the cycle while lactoferrin displayed a clear correlation with neutrophil counts. In 1 case with persistent agranulocytosis myeloperoxidase was normal but lactoferrin was extremely low. During the regeneration phase of drug-induced neutropenia neutrophil counts and serum lactoferrin increased in a parallel fashion. Since serum myeloperoxidase was normal during profounded neutropenia it is suggested to derive primarily from myeloperoxidase-rich granulopoietic precursor cells of the marrow. Serum lactoferrin on the other hand seems to derive from leakage of more granulopoietic cells of blood and marrow. Studies of neutrophil proteins of serum may aid in evaluation of neutropenic patients.
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PMID:Serum myeloperoxidase and lactoferrin in neutropenia. 19 Jun 72

Myeloperoxidase, restricted to primary granules, and lactoferrin, restricted to secondary granules, were determined in plasma and neutrophils of peripheral blood in chronic granulocytic leukaemia (CGL). Plasma myeloperoxidase was increased 2-3 times while plasma lactoferrin increased 2-8 times. This discrepancy indicates different modes of release or elimination. A correlation was found between the leucocyte count and plasma myeloperoxidase or lactoferrin. A correlation was also found between cellular and plasma levels of lactoferrin but not for myeloperoxidase indicating the source for plasma lactoferrin to be circulating leucocytes, which may not be the case for plasma myeloperoxidase. Decreased neutrophil lactoferrin was found in 71% of the CGL cases while myeloperoxidase was decreased in 18%. Serial studies on individual CGL subjects showed low cellular lactoferrin during phases with rapidly expanding leucocytosis indicating defective maturation of neutrophils or abnormal release because of prolonged intravascular life-span.
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PMID:Myeloperoxidase and lactoferrin of blood neutrophils and plasma in chronic granulocytic leukaemia. 19 Jun 73

The subcellular localization of granulocyte collagenase, elastase and chymotrypsin-like cationic protein was determined using velocity centrifugation of cytoplasmic granules of human polymorphonuclear leukocytes. The proteases were assayed by immunochemical and enzymatic methods. Measurements of lactoferrin and myeloperoxidase distinguish exactly between constituents of specific and azurophil granules. Collagenase, elastase and chymotrypsin-like cationic proteins showed an almost identical sharp and unimodal distribution. They co-sedimented with myeloperoxidase demonstrating that these enzymes are localized exclusively in the azurophil granules.
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PMID:Localization of chymotrypsin-like cationic protein, collagenase and elastase in azurophil granules of human neutrophilic polymorphonuclear leukocytes. 19 54


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