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)

Exogenous hen lysozyme or endogenous rat lysozyme labeled with 131I was intravenously injected to rats with the same dosage, respectively, and the uptake and degradation of injected 131I-labeled rat lysozyme in liver and kidney were studied in comparison with those of 131I-labeled hen lysozyme. 1. Although the serum levels of both enzymes injected were almost indentical during the first 6 h, the liver uptake of 131I-labeled hen lysozyme was 2.2-fold more than that of 131I-labeled rat lysozyme at the peak time of 5 min after injection. The uptake and clearance of 131I-labeled rat lysozyme in the kidney were exclusively slow as compared with those of 131I-labeled hen lysozyme. 2. The intracellular distribution in the liver and kidney were examined by the differential centrifugation after injection of each lysozyme. The protein-bound radioactivity of each subcellular fraction was found to be the highest in the 12 000 X g (10 min) fraction in the liver and the 19 600 X g (20 min) fraction in the kidney. The relative specific activity of 12 000 X g fraction of the liver after injection increased with the time lapse. On the other hand, the relative specific activity of 105 000 X g (1 h) fraction of the liver attained a maximum within 5 min after injection and thereafter decreased. It was assumed that the mechanism of the uptake of injected 131I-labeled rat lysozyme in the liver and kidney was similar to that of 131I-labeled hen lysozyme. 3. The degradation of exogenous or endogenous lysozyme in subcellular particles was examined. From the effect of pH, activator and inhibitor on the degradation, the proteolytic enzyme to degrade the injected 131I-labeled hen lysozyme was indicated to be mainly cathepsin BL, with the optimal pH of about 5.0, and the injected 131I-labeled rate lysozyme was mainly degraded by cathepsin D, with the optimal pH of about 3.5 The in vitro degradation of exogenous and endogenous lysozymes showed a tendency similar to the in vivo clearance from the liver and kidney.
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PMID:Studies on biotransformation of lysozyme. III. Comparative studies on biotransformation of exogenous and endogenous lysozyme in rats. 1 53

The number of white blood cells and of polymorphonuclear leukocytes remained unchanged in vervet monkeys (Cercopithecus aethiops) receiving a "O" protein diet. The motility of the polymorphonuclear leukocytes and their phagocytic and killing indices with and without leukokinin stimulation decreased in protein-depleted animals. Acid cathepsin decreased, DNA relatively increased, and peroxidase, alkaline phosphatase, acid phenylphosphatase, and lysozyme reached higher levels in the polymorphonuclear leukocytes of animals on a "O" protein diet.
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PMID:Polymorphonuclear neutrophilic leukocytes in protein deficiency. 40 70

Renal extraction of low molecular weight proteins (LMWP) accounts for 30% to 80% of their total metabolic clearance. Extraction includes glomerular filtration, proximal tubular uptake, and intralysosomal proteolysis. To characterize the anatomic sites and enzymes involved in digestion of reabsorbed LMWP, the lysosomal proteases, cathepsin B and L, were measured by ultramicroassay in isolated S1, S2 and S3 segments of the proximal tubule of proteinuric rats. Increased glomerular filtration and tubular uptake of LMWP were induced by i.v. and i.p. injections of myoglobin and cationic and anionic lysozyme. Both cationic lysozyme and myoglobin increased cathepsin B and L activities in the proximal tubule, while anionic lysozyme had no effect. Morphologic examination of kidney tissue suggested that proximal tubular uptake of anionic lysozyme was negligible in comparison with the cationic form. Hence, only LMWP absorbed by the proximal tubule cells stimulated cathepsin B and L activities. Proximal tubular uptake of cationic lysozyme was determined by measurement of lysozyme activities in S1, S2, and S3. S1 segments contained the highest lysozyme activity, while S2 and S3 had much lower activities, and cathepsin B and L activity following cationic lysozyme injection was stimulated only in S1 segments. These results suggest that cathepsin B and L participate in lysosomal digestion of certain LMWP. Furthermore, the activities of cathepsin B and L adapt to increased uptake of LMWP. To gain additional insight into the mechanism of cathepsin adaptation, the cathepsin B and L activities were measured following injection of dextran with a similar low molecular weight.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of low molecular weight proteins and dextran on renal cathepsin B and L activity. 169 Mar 11

The importance of granular (lysosomal) enzymes from neutrophils in producing the tissue damage of acute inflammation has been suggested by much indirect and some direct evidence. This study has investigated the kinetics of release and subsequent fate of granular enzymes from phagocytizing human leukocytes The following observations are made: (a) During phagocytosis, the granular enzyme lysozyme is released from leukocytes into the extracellular medium. (b) Release of lysozyme increases as phagocytic challenge increases, but attains a maximum. (c) Release of lysozyme accompanies phagocytosis and is not a delayed event. (d) The lack of release of a nongranular enzyme, lactic dehydrogenase, indicates that cell damage is not a necessary condition of enzyme release. (e) Like lysozyme, beta-glucuronidase is released from phagocytizing leukocytes. Acid alpha-naphthyl phosphatase and cathepsin also appear to be released, but are not found in appreciable amounts in the extracellular medium, in part because of their lability in solution. These results support the concept that extracellular release of granular enzymes may be a useful secretory function of inflammatory leukocytes which becomes damaging to the host in certain circumstances.
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PMID:The mobilization and extracellular release of granular enzymes from human leukocytes during phagocytosis. 502 60

Mouse mononuclear phagocytes cultivated in 50 per cent newborn calf serum medium pinocytize actively and form large numbers of phase-dense granules as well as three hydrolytic enzymes. When such cells are then placed in 1 per cent newborn calf serum they illustrate (a) a low level of pinocytic activity, (b) a shrinkage in granule size, and (c) a loss in cell protein, acid phosphatase, beta-glucuronidase, and cathepsin. Examination of the extracellular medium revealed no detectable hydrolase activity. The reintroduction of cells into high levels of serum again resulted in granule and enzyme formation. Cells rapidly incorporated fluorescein-conjugated calf serum proteins into the phase-dense granules. The fluorescence of labeled granules was lost during an 18 hour period in non-fluorescein-containing medium. Crystalline egg white lysozyme was concentrated in the macrophages. Approximately 80 per cent of the cell-associated enzyme was lost during a 24 hour washout period in either 1 or 50 per cent serum medium. No enzymatic activity could be recovered in the medium. Colloidal gold was taken up and concentrated in macrophage granules. Quantitative assays revealed this particle to be conserved during a 24 hour washout period.
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PMID:The in vitro differentiation of mononuclear phagocytes. 3. The reversibility of granule and hydrolytic enzyme formation and the turnover of granule constituents. 532 Mar 3

Crystalloid inclusions or "pole bodies" observed in brain macrophages in human demyelinating disease represent a morphological enigma. Similar inclusions were detected in brain macrophages from the GFAP-IL3 mouse, a transgenic murine model for macrophage mediated demyelination. Mice also showed inclusions in hematopoietic tissue. They appear to be related to phagocytosis and secretion, respectively, as evidenced by the fact that in phagocytosing cells they often merged with lysozomes and that affected cells showed empty channels open to the interstitium. Based on ultrastructural and immunolocalization studies using chaperonin-10, lysozyme, and cathepsin the authors suggest that these inclusions are consistent with phagocytosis-related secretory products. This study may provide insight into the nature and significance of similar macrophage inclusions recently identified in multiple sclerosis.
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PMID:Crystalloid inclusions in brain macrophages and hemopoietic tissue in GFAP-IL3 mice resemble inclusions identified in multiple sclerosis. 1058 66

Delta(9)-tetrahydrocannabinol (THC) causes an antigen-dependent defect in the ability of macrophages to activate helper T cells, and this drug-induced impairment is mediated through the peripheral CB2 receptor. Various requirements for the processing of the antigen, lysozyme, were examined to determine where along the pathway THC exerts its influence. A THC-exposed macrophage hybridoma inefficiently stimulated interleukin-2 secretion by a helper T cell hybridoma in response to native lysozyme and its reduced form, suggesting that disulfide bond reduction was unaffected. Cell surface expression of major histocompatibility complex class II molecules was normal on THC-exposed macrophages. The drug-exposed macrophages also competently presented a lysozyme peptide to the T cells, indicating that the class II molecules were functional. The proteolytic activity of two thiol cathepsins was unaltered, but aspartyl cathepsin D activity was significantly increased in THC-exposed macrophages. Thus, selective up-regulation of aspartyl cathepsin activity accompanied the deficiency in lysozyme processing and may contribute, at least in part, to the antigen-dependent processing defect in THC-exposed macrophages.
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PMID:Delta(9)-tetrahydrocannabinol selectively increases aspartyl cathepsin D proteolytic activity and impairs lysozyme processing by macrophages. 1070 85

To address the role of different proteases in degradation of antigen destined for MHC class II-restricted presentation, we generated cathepsin-deficient mice carrying a transgenic B cell receptor (BCR) specific for hen egg lysozyme (HEL). We demonstrate that degradation of HEL in B lymphocytes is highly processive and does not result in discrete processing intermediates. Moreover, degradation of HEL does not require initial unlocking of the antigen by any of the cathepsins tested. Using mass spectrometry and microsequencing, we show that all major cathepsins (CatS, CatL, CatB, and CatD) digest HEL in vitro with considerable redundancy, although some preferential cleavages are evident. These observations have a functional correlate: when triggered by cathepsin S-deficient antigen-presenting cells, T cells that recognize different HEL epitopes fail to present two HEL-derived epitopes, while a third epitope is presented independently of the activity of cysteine proteases. We conclude that the proteolytic processing machinery is redundant, and that several proteases can substitute for each other to degrade a given antigen. However, a certain degree of proteolytic specificity is demonstrable for the generation of particular epitopes, notably by CatS.
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PMID:Specific role for cathepsin S in the generation of antigenic peptides in vivo. 1181 65

Retrospective studies have shown antineutrophil cytoplasmic antibody (ANCA) positivity in patients treated for Graves' hyperthyroidism; ANCA has been attributed to either antithyroid drugs or to the disease itself. The aim of this study was to determine ANCA in Graves' disease patients at diagnosis and after treatment with methimazole and to evaluate the relationship between ANCA and hyperthyroidism evolution. Thirty patients recently diagnosed with Graves' hyperthyroidism were prospectively studied. ANCA were determined by indirect immunofluorescence. ANCA autoantibodies against specific antigens (proteinase 3, myeloperoxidase, bactericidal/permeability-increasing protein (BPI), cathepsin, lysozyme, elastase, and lactoferrin) were detected by ELISA. The median observation period was 22 months. Kaplan-Meier analysis was performed to identify ANCA as an outcome variable. Twenty patients (67%) were ANCA positive before the onset of treatment, and four (19%) remained positive after 1 yr of antithyroid drug treatment. No differences were observed in any clinical or analytical features between patients with or without positive ANCA. Before treatment, BPI-positive patients required radioiodine treatment or presented relapse more rapidly than BPI-negative patients (log-rank test P < 0.0002). Patients with Graves' hyperthyroidism show positive ANCA before medical treatment, which points to a relationship with the autoimmune disease itself. Our results suggest that BPI-positive patients tend to relapse with antithyroid medication.
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PMID:Frequency of antineutrophil cytoplasmic antibody in Graves' disease patients treated with methimazole. 1272 67

New cysteine protease inhibitors in human tears and milk and their medical significance are reviewed in this paper. As protective components against bacterial infection in the eyes, we detected four kinds of anti-bacterial proteins in normal human tears including lysozyme and three kinds of cysteine protease inhibitors. Using our reverse zymography of normal tears, three kinds of cysteine protease inhibitors were found to be 78kDa, 20kDa and 15kDa and were determined to be lactoferrin, Von Ebner's Gland (VEG) protein and cystatin S, respectively. All of them belong to the cystatin super family and VEG protein and cystatin S are well known cysteine protease inhibitors. The C-terminus area 17mer peptide, Y679-K695, of lactoferrin showed strong homology with a common active domain of the cystatin family and the synthesized peptide showed inhibition of cysteine proteases. Not only were disease-specific changes found in these inhibitor profiles, but also disease-specific new inhibitors in patients tears with certain autoimmune diseases. A 35kDa inhibitor, which was detected specifically in tears with Behcet's disease, an typical autoimmune disease, was determined to be a lacrimal acidic proline-rich protein based on the N-terminus sequence analysis. A 65kDa inhibitor of tears with Harada's autoimmune disease was determined to be an Ig heavy chain V-III region. In addition, lactoferrin content in Harada's disease was very low. We found two cathepsin inhibitors in bovine milk using reverse zymography, namely lactoferrin and beta-casein. The L133-Q151, in the human beta-casein molecule is the active inhibitory domain. They may play an important role in antiseptic and anti-infectious functions.
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PMID:Medical significance of cysteine protease inhibitors in mammalian secretory fluids. 1367 84


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