Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The activities of 30 different lysosomal enzymes were determined in vitro in the presence of the sulphated glycosaminoglycans, heparin and chondroitin sulphate, all the enzymes being measured on a density-gradient-purified lysosomal fraction. 2. Each enzyme was studied as a function of the pH of the incubation medium. In general the presence of sulphated glycosaminoglycans induced a strong pH-dependent inhibition of lysosomal enzymes at pH values lower than 5.0, with full activity at higher pH values. However, in the particular case of lysozyme and phospholipase A2 the heparin-induced inhibition was maintained in the pH range 4.0-7.0. 3. For certain enzymes, such as acid beta-glycerophosphatase, alpha-galactosidase, acid lipase, lysozyme and phospholipase A2, the pH-dependent behaviour obtained in the presence of heparin was quite different to that obtained with chondroitin sulphate, suggesting the existence of physicochemical characteristic factors playing a role in the intermolecular interaction for each of the sulphated glycosaminoglycans studied. 4. Except in the particular case of peroxidase activity, in all other lysosomal enzymes measured the glycosaminoglycan-enzyme complex formation was a temperature-and time-independent phenomenon. 5. The effects of the ionic strength and pH on this intermolecular interaction reinforce the concept of an electrostatic reversible interaction between anionic groups of the glycosaminoglycans and cationic groups on the enzyme molecule. 6. As leucocytic primary lysosomes have a very acid intragranular pH and large amounts of chondroitin sulphate, we propose that this glycosaminoglycan might act as molecular regulator of leucocytic activity, by inhibiting lysosomal enzymes when the intragranular pH is below the pI of lysosomal enzymes. This fact, plus the intravacuolar pH changes described during the phagocytic process, might explain the unresponsiveness of lysosomal enzymes against each other existing in primary lysosomes as well as its full activation at pH values occurring in secondary lysosomes during the phagocytic process.
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PMID:Physicochemical characteristics of the glycosaminoglycan-lysosomal enzyme interaction in vitro. A model of control of leucocytic lysosomal activity. 1 48

Five cases of acute promyelocytic leukaemia (A.P.L.) are investigated for peroxidase, PAS, toluidine blue, astra blue, alpha-naphthyl esterase, double esterase incubation (naphthol-AS plus naphthol-AS-D chloroesterase), and cellular lysozyme activity. These cytochemical investigations may contribute further characterization of the morphologic type.
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PMID:Cytochemical study of acute promyelocytic leukaemia. 4 71

Earlier studies on fetal thymus suggested that certain of the large pyroninophilic cells found there might have a hemopoietic role, and it was decided to determine the nature of these cells using histochemical and immunohistochemical methods. Thymic tissue from aborted fetuses, stillbirths, and neonatal deaths was examined histochemically using methods for the detection of chloroacetate esterase, peroxidase, and pseudoperoxidase, and by staining techniques for mast cells and eosinophils. Tissue was also examined using the indirect immunoperoxidase method for the presence of hemoglobin A (HbA) and F (HbF), for lysozyme (muramidase) and immunoglobins alpha, mu, gamma, kappa, lambda. Positive staining to some degree was seen in cells in the connective tissue stroma using all methods, and the cells stained corresponded to one or another of the types of pyroninophilic cells present. The finding of large cells with positive chloroacetate esterase and antilysozyme indicates the presence of granulopoiesis. Similarly, the presence of large nucleated cells with pseudoperoxidase and anti-hemoglobin (A and F) staining indicates the presence of erythropoiesis. Plasma cells were present in small numbers.
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PMID:Evidence for significant hematopoiesis in the human thymus. 5 99

Degradation of myelin basic protein during incubations with high concentrations of horseradish peroxidase has been demonstrated [Johnson & Cammer (1977) J. Histochem. Cytochem.25, 329-336]. Possible mechanisms for the interaction of the basic protein with peroxidase were investigated in the present study. Because the peroxidase samples previously observed to degrade basic protein were mixtures of isoenzymes, commercial preparations of the separated isoenzymes were tested, and all three degraded basic protein, but to various extents. Three other basic proteins, P(2) protein from peripheral nerve myelin, lysozyme and cytochrome c, were not degraded by horseradish peroxidase under the same conditions. Inhibitor studies suggested a minor peroxidatic component in the reaction. Therefore the peroxidatic reaction with basic protein was studied by using low concentrations of peroxidase along with H(2)O(2). Horseradish peroxidase plus H(2)O(2) caused the destruction of basic protein, a reaction inhibited by cyanide, azide, ferrocyanide, tyrosine, di-iodotyrosine and catalase. Lactoperoxidase plus H(2)O(2) and myoglobin plus H(2)O(2) were also effective in destroying the myelin basic protein. Low concentrations of horseradish peroxidase plus H(2)O(2) were not active against other basic proteins, but did destroy casein and fibrinogen. Although high concentrations of peroxidase alone degraded basic protein to low-molecular-weight products, suggesting the operation of a proteolytic enzyme contaminant in the absence of H(2)O(2), incubations with catalytic concentrations of peroxidase in the presence of H(2)O(2) converted basic protein into products with high molecular weights. Our data suggest a mechanism for the latter, peroxidatic, reaction where polymers would form by linking the tyrosine side chains in basic-protein molecules. These data show that the myelin basic protein is unusually susceptible to peroxidatic reactions.
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PMID:Proteolytic and peroxidatic reactions of commercial horseradish peroxidase with myelin basic protein. 7 59

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

Data on the role of oral lysozyme, ribonuclease, deoxyribonuclease and peroxidase in antimicrobial defense of the macroorganism are reviewed. The biochemical and physiological properties of the enzymes secreted by salivary glands and released from emigrating leukocytes are discussed. Spectra of antimicrobial action of the enzymes and participation of these enzymes in maintaining the stability of oral biocenosis are described as well as the regulation of these enzymatic activities and the pathogenetic significance of impairments in their secretion. The most perspective aspects of the problems discussed are outlined for further investigation.
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PMID:[Enzymatic mechanisms for antimicrobial protection of the oral cavity]. 20 88

Polar solvents induce terminal differentiation in the human promyelocytic leukemia cell line HL-60. The present studies describe the functional changes that accompany the morphologic progression from promyelocytes to bands and poly-morphonuclear leukocytes (PMN) over 9 d of culture in 1.3 percent dimethylsulfoxide (DMSO). As the HL-60 cells mature, the rate of O(2-) production increase 18-fold, with a progressive shortening of the lag time required for activation. Hexosemonophosphate shunt activity rises concomitantly. Ingestin of paraffin oil droplets opsonized with complement or Ig increases 10-fold over 9 d in DMSO. Latex ingestion per cell by each morphologic type does not change significantly, but total latex ingestion by groups of cells increases with the rise in the proportion of mature cells with greater ingestion capacities. Degranulation, as measured by release of beta-glucuronidase, lysozyme, and peroxidase, reaches maximum after 3-6 d in DMSO, then declines. HL-60 cells contain no detectable lactoferrin, suggesting that their secondary granules are absent or defective. However, they kill staphylococci by day 6 in DMSO. Morphologically immature cells (days 1-3 in DMSO) are capable of O(2-) generation, hexosemonophosphate shunt activity, ingestion, degranulation, and bacterial killing. Maximal performance of each function by cells incubated in DMSO for longer periods of time is 50-100 percent that of normal PMN. DMSO- induced differentiation of HL-60 cells is a promising model for myeloid development.
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PMID:Functional changes in human leukemic cell line HL-60. A model for myeloid differentiation. 22 36

A group of very similar cell lines was established from peripheral blood or bone marrow of 12 patients with a variety of disorders. The cells in these cell lines were uniform and round in shape. They grew as single-cell suspensions or as aggregates of small numbers of cells in stationary culture. The most striking characteristic of these lines was the lack of cells with surface immunoglobulin or with demonstrable immunoglobulin synthesis. This lack of immunoglobulin synthesis and their special growth characteristics distinguished them from the lymphoblastoid B cell lines previously described. The cells of these unusual cell lines had strong Fc receptors and C3 receptors and expressed Ia antigens. They did not form rosettes with sheep erythrocytes and did not have detectable levels of terminal deoxynucleotidyltransferase. They did not secrete lysozyme and failed to stain for peroxidase. The presence of the Epstein-Barr virus nuclear antigen in the cells indicated the presence of Epstein-Barr viral genome. The possibility that these cells represent some type of precursor cell in the B cell lineage is discussed, but the exact cellular origin remains to be ascertained.
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PMID:Human cell lines containing Epstein-Barr virus but distinct from the common B cell lymphoblastoid lines. 23 May 17

A simple cytochemical and cytobacterial method for the simultaneous demonstration of peroxidase and lysozyme (muramidase) activities in individual cells was devised. In characterization of myeloid and monocyte series, the combination of these myeloid- and monocyte-specific enzymes not only was more informative than a single enzyme but made it easier to differentiate acute myelomonocytic leukemia, with higher lysozyme activity, from acute myeloid leukemia, with higher peroxidase activity. Acute lymphocytic leukemia had no lysozyme or peroxidase activity.
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PMID:Simultaneous demonstration of peroxidase and lysozyme activities in leukemic cells. 26 61

Twelve cases of pure acute monocytic leukemia in adults were studied. They were selected on the basis of the morphology of the blast cells on Romanowsky-stained smears of blood and bone marrow, as well as positivity of the cells for the naphthol ASD acetate esterase reaction specifically inhibited by sodium fluoride. There was no sex predominance. Neoplastic involvement of the skin and/or gingiva was very frequent. The leukemic proliferation in blood and bone marrow consisted of monoblasts, promonocytes and monocytes. The peroxidase reaction was negative or only faintly positive. Serum and urinary lysozyme levels were increased. The blast cells retained their ability to stimulate, in vitro, colony formation by normal bone marrow cells used as targets. All of these characteristics permit specific identification of this type of acute leukemia. The prognosis is grim: only five of 12 patients achieved complete remission, and four of these five had relapses in less than 14 months; the median survival was five months.
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PMID:Pure acute monocytic leukemia. A study of 12 cases. 30 66


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