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)

Lysis protein T of phage T4 is required to allow the phage's lysozyme to reach the murein layer of the cell envelope and cause lysis. Using fusions of the cloned gene t with that of the Escherichia coli alkaline phosphatase or a fragment of the gene for the outer membrane protein OmpA, it was possible to identify T as an integral protein of the plasma membrane. The protein was present in the membrane as a homooligomer and was active at very low cellular concentrations. Expression of the cloned gene t was lethal without causing gross leakiness of the membrane. The functional equivalent of T in phage lambda is protein S. An amber mutant of gene S can be complemented by gene t, although neither protein R of lambda (the functional equivalent of T4 lysozyme) nor S possess any sequence similarity with their T4 counterparts. The murein-degrading enzymes (including that of phage P22) have in common a relatively small size (molecular masses of ca. 18,000) and a rather basic nature not exhibited by other E. coli cystosolic proteins. The results suggest that T acts as a pore that is specific for this type of enzyme.
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PMID:Lysis protein T of bacteriophage T4. 146

Investigations were performed to become acquainted with the immunohistochemical features of foam cells localized perivascular and intratumoral in neoplasms of neuroectodermal origin. Antibodies against lysozyme (muramidase) (LO), alfa 1-antitrypsin (AT), protein S-100 and glial fibrillary acid protein (GFAP) were used. A weak or medium intense reaction result has been obtained in the cytoplasm of the foam cells if antibodies against LO, and alfa 1-antitrypsin and almost negative result if antibodies against protein S-100 and GFAP were used. Only very few cells which differ from the foam cells morphologically were very intense stained with primary antibodies against LO and alfa 1-antitrypsin. In accordance with the present views the LO and AT positive cells were recognized as macrophages. The application of macrophage markers did not allow us to ascribe unequivocally the foam cells macrophage-like or histiocyte-like properties. May be that the foam cells in tumors of perivascular and intratumoral localization present another phenotypic defined group of histiocytes, despite their morphological similarity to those cells derived from smooth muscle cells of arterial blood vessels observed in arteriosclerosis.
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PMID:Immunocytochemical characteristics of perivascular and intratumoral foam cells in neoplasms of neuroectodermal origin with lysozyme, alfa1-antitrypsin, protein S-100 and GFAP. 196 30

Eighteen granular cell tumors from various sites were examined with antisera directed against protein S-100, neuron specific enolase (NSE), alpha-1-antichymotrypsin, and alpha-1-antitrypsin, glial fibrillary acidic protein (GFAP), lysozyme, factor VIII-related antigen, myoglobin and vimentin, as well as with a monoclonal antibody (lu-5) directed against a panepithelial marker. The immunocytochemical reaction pattern of the tumors was heterogeneous. The brain and pituitary tumors and one thyroid tumor reacted for alpha-1-antichymotrypsin and alpha-1-antitrypsin, but not for S-100 protein and NSE. However, tumors from other sites showed immunoreactions for S-100 protein and NSE and some also for vimentin. Reactions for alpha-1-antichymotrypsin and alpha-1-antitrypsin were not observed. All other reactions were similarly negative. We conclude that the morphologically homogeneous group of granular cell tumors is biologically heterogeneous.
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PMID:Granular cell tumors: evidence for heterogeneous tumor cell differentiation. An immunocytochemical study. 288 72

Giant cell tumor of the bone is usually located within the epiphysis of a long bone, the majority of the lesions occurring in the third and fourth decades of life. We report an unusual case of giant cell tumor (GCT) arising in the parietal skull bone of a 9-year-old girl. The tumor exhibited histologic findings typical for GCT, with conspicuous intravascular giant cells. Based on microscopic features, not only conditions like aneurysmal bone cyst or bone changes associated with hyperparathyroidism but also tumors such as chondroblastoma or osteosarcoma had to be considered. Immunohistochemistry revealed strong reactivity of the tumor giant cells and normal bone osteoclasts with CD68 but not Mac-387; tumor stromal cells were uniformly negative for both. The stromal cells exhibited two immunohistochemically distinct phenotypes. One, involving 50-80% of the tumor cells, exhibited negative lysozyme staining with positivity of proliferating cell nuclear antigen (PCNA) in about 30% of the nuclei. The other showed reactivity with lysozyme but negative PCNA staining. Immunohistochemistry thus helped to distinguish chondroblastoma and osteosarcoma, in which lysozyme positivity would reside in macrophages but not within stromal cells. Instead, chondroblastoma would exhibit protein S-100 positivity in the tumor cells. The biological behavior of GCT is difficult to predict based on morphology alone, although the malignant potential seems to rest in the stromal cells rather than the giant cells. Specifically, in reported cases, the intravascular occurrence of giant cells in GCT is not associated with an increased incidence of metastasis.
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PMID:Giant cell tumor in the skull of a 9-year-old child: immunohistochemistry to confirm a diagnosis rare for age and site. 859 62

The collective immunohistochemical expression of human lysozyme, human alpha-1-antitrypsin, human CD3 antigen, calf vimentin, human keratins, human lambda light chains,canine immunoglobulins IgG, IgM, and bovine protein S-100 has been analyzed on formalin-fixed, paraffin-embedded tissue sections of 25 spontaneous canine transmissible venereal tumors (CTVT) from both genital and extragenital locations using the avidin-biotin-peroxidase complex technique. Lysozyme immunoreactivity was detected in 10/25 CTVT, alpha-1-antitrypsin in 14/25 CTVT, and vimentin in 25/25 CTVT. All CTVT cells were negative to keratins 5 + 8 of the Moll catalogue (RCK-102), S-100 protein, lambda light-chain immunoglobulins, IgG, IgM, and CD3 antigen. The intratumoral T-and B-lymphocyte infiltrate was differentiated using CD3 antigen, lambda light-chain immunoglobulins, IgG, and IgM, and this technique could be useful to evaluate the regressive or progressive growth stage of venereal tumors. Our findings support the hypothesis of a histiocytic immunophenotype for CTVT, and these staining techniques could be used in the differential diagnosis with lymphomas.
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PMID:Immunohistochemical characterization of canine transmissible venereal tumor. 874 Jun 98

The role of protein structure in the reactivity of the four disulfide (S-S) bridges of lysozyme was studied using Raman spectroscopy and molecular modelling. The experimental kinetics of S-S bridge reduction by tris-2-carboxyethyl phosphine (TCEP) was obtained by monitoring the protein S-S Raman bands. The kinetics are heterogeneous and were fitted using two apparent reaction rate constants. Kinetic measurements performed at different pH values indicate only moderate charge effects. The two intrinsic reaction rate constants derived for the neutral TCEP species were 0.45 and 0.052 mol(-1) s(-1), respectively. The molecular dynamics simulation of the reactants encounter shows that the accessibility of the lysozyme S-S bridges by TCEP decreases in the following order: cys30-cys115 > cys6-cys127 > cys64-cys80 > cys76-cys94. This simulation also illustrates the reaction mechanism which consists of a local unfolding followed by the reduction of the exposed S-S bridge. The Gibbs free energy for local unfolding was evaluated by comparing the actual reaction rate constant with that of a model system containing a fully exposed S-S bridge (oxidized glutathione). These values corresponding to the fast- and slow-reaction rate-constants were 8.5 and 13.8 kJ mol(-1), respectively. On the other hand, Raman measurements, as well as the molecular dynamics simulations, strongly suggest that the protein global unfolding following S-S bridge cleavage has only limited effects in stabilizing the reaction products.
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PMID:Protein S-S bridge reduction: a Raman and computational study of lysozyme interaction with TCEP. 1932 88