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)

The reactivation of reduced lysozyme, whose 6 COOH-terminal amino acid including cysteine 127 were cut off, was studied. The results show that the disulfide bridge I-VIII as well as the COOH-terminal hexapeptide do not play a decisive role in the acquisition of the native 3-dimensional structure of the enzyme.
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PMID:Reoxidation of reduced hen egg white lysozyme fragment 1-123. 70 10

Studies on the mechanism of the glutathione regeneration (Saxena, V.P., and Wetlaufer, D.B. (1970) Biochemistry 9, 5015-5023) of hen egg lysozyme have been carried out. The first two stoichiometric disulfides in lysozyme are formed about 8 times more rapidly than the second two. Almost no enzymic activity is regained until the first two disulfides are formed, thus ruling out an all-or-none mechanism. The disulfide peptides formed early in the regeneration have been isolated and identified. The results show a limited search of folding intermediates, and outline a folding pathway. The early disulfides involve cysteinyl residues III, IV, V, and VI. At the same time cysteinyl residues I, II, VII, and VIII are still reduced, as demonstrated by their isolation as S-alkylated derivatives. At slightly later times a peptide is found which contains the (native) disulfide between cysteinyl residues II and VII. It is likely, but as yet unproven, that formation of disulfide I-VIII completes the cross-linking of lysozyme.
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PMID:The folding pathway of reduced lysozyme. 127 Apr 40

Immunohistochemical study of giant cell tumor of bone (GCT) was carried out utilizing a panel of monoclonal antibodies including those against lysozyme, alpha-antichymotrypsin (AACT), vimentin (Vim), M718, HLA-DR, S-100 protein, epithelial membrane antigen (EMA), leukocyte common antigen (LCA), KB90, factor VIII related antigen (F VIII) against stromal cells and giant cells in 20 cases of GCT, with one case of prolonged continuously cultured cells GCT (GT 15). The results showed that stromal cells could be divided into two subgroups. Mesenchymal stromal cells labelled only with vimentin and were regarded as being derived from undifferentiated mesenchymal cells of bone marrow, while macrophage-like stromal cells labelled with antigens and were found to be present in mononuclear phagocytes. We believe this to be the first report that some stromal cells reacted positively with S-100 protein. Multinucleated giant cells were AACT and M718 positive, indicating their close relationship to macrophage-like stromal cells. The prolonged cultured cells accepted labelling with vimentin only indicating that all macrophage-like stromal cells disappeared after several subcultures and the only cells that could continue to be subcultured were the mesenchymal stromal cells.
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PMID:Giant cell tumors of bone. An immunohistochemical study. 260 17

We used immunohistochemistry to evaluate four cytologically malignant cutaneous neoplasms on the face or neck of elderly individuals. All four lesions were composed of a dermal proliferation of spindle and pleomorphic giant cells. Differential diagnosis included spindle cell carcinoma, atypical fibroxanthoma, malignant melanoma, leiomyosarcoma, and angiosarcoma. All four neoplasms were strongly immunoreactive for vimentin and negative for cytokeratin, S100 protein, desmin, and factor-VIII-related antigen. Focal immunoreactivity for lysozyme and/or a1-antichymotrypsin was seen in the giant cells of each lesion. These results supported the diagnosis of atypical fibroxanthoma in each instance. Immunohistochemical staining can provide useful information for distinguishing among malignant cutaneous spindle cell tumors.
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PMID:Immunohistochemistry: a useful adjunct in the evaluation of malignant cutaneous spindle cell tumors. 320 Dec 97

The ultrastructural features of 8 human cardiac myxomas were analyzed and correlated with immunohistochemical data, with the aim to clarify the characteristics of the cell lines involved in the tumor genesis. Immunohistochemical studies were performed to detect the presence and the distribution of intracytoplasmic filaments (vimentin, desmin, actin, myosin) as well as myoglobin and factor VIII-related antigen, albumin, and lysozyme. Eighty percent of myxoma cells were simultaneously positive for vimentin, desmin, and actin, whereas 30% of them stained with antifactor VIII and antivimentin antibodies. The submicroscopic analysis revealed two main cell populations: (1) one composed of stellate-shaped cells with scanty organelles and sparse hyaloplasmic filaments scattered throughout the myxoid stroma and forming a loose network with their projections; (2) another one included cells with more cytoplasmic organelles, intermediate filaments, and myofilaments arranged either singly or in both solid and hollow cord-like structures. Our results support the hypothesis that cardiac myxoma may originate from a reserve multipotent mesenchymal cell able to differentiate more or less completely along two major evolutional lines: myoid and endothelial. The tumor tissue thus seems to be involved in vessel formation, suggesting a growth pattern akin to that manifested in other forms of endocardial pathological reactivity in which reserve mesenchymal cells are engaged.
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PMID:Ultrastructural and immunohistochemical contribution to the histogenesis of human cardiac myxoma. 336 83

Systemic mastocytosis (SM) can be regarded as a tumorous proliferation of tissue mast cells (TMC) involving various organs, particularly the bone marrow. The infiltrates, however, are by no means composed exclusively of TMC, but also contain eosinophils and lymphocytes. The varying composition of the TMC infiltrates and the immunohistological characteristics of the lymphatic cells were the main subjects of investigation in this study. Three different types of bone marrow infiltrates could be identified: (1) A pure mastocytic infiltrate. (2) A mixed mastocytic/lymphocytic infiltrate. (3) A predominantly lymphocytic infiltrate containing loosely-scattered TMC. The mixed mastocytic/lymphocytic infiltrate seems to be a unique finding confined to the bone marrow in cases of SM, and is not detected in this conformation in other tissue sites normally involved in SM (spleen, liver, lymph nodes and skin), nor in cases of malignant mastocytosis. The lymphoid cells could be identified immunohistologically as being an admixture of T lymphocytes and B lymphocytes, while NK cells were virtually absent from the composite nodules. The TMC reacted strongly with antibodies (monoclonal or polyclonal) against vimentin, common leucocyte antigen, lysozyme, alpha 1-antichymotrypsin and alpha 1-antitrypsin, but were negative with a variety of other antibodies tested (UCHL1, MB1, Ki-B3, Leu-7, KL1, desmin, S-100 protein, F VIII-related antigen and chromogranin A).
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PMID:Lymphoid cells and tissue mast cells of bone marrow lesions in systemic mastocytosis: a histological and immunohistological study. 340 82

Thirty-nine skin tumors of epithelial, mesenchymal, and neuroectodermal origin were studied using antibodies against intermediate filaments and other cell proteins. Formol-fixed and paraffin-embedded material was reconstituted and stained with antibodies against epithelial cells (keratin, epithelial membrane antigen, carcinoembryonic antigen), mesenchymal and histiocytic cells (vimentin, alpha-1-antichymotrypsin, alpha-1-antitrypsin, lysozyme), nerve tissue (neurofilament, glial fibrillary acidic protein, myelin basic protein, myelin-associated protein, neuron-specific enolase), vessels (factor-VIII-related protein), basal cell lamina (laminin) and S-100 protein. Tumor cells displayed the same antibody pattern found in the normal cell type. It is recommended that immunotyping be started with three antibodies to allow gross classification into epithelial (keratin positive), mesenchymal (vimentin positive) and neuroectodermal (vimentin and S-100 protein positive) tumors; then, in a second step, the tumors can be subclassified by the other more specific antibodies listed above. All antibodies used in this study are commercially available and provide reliable results.
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PMID:[Immunohistologic differential diagnosis of skin tumors in routinely embedded paraffin sections]. 355 72

The disulfide peptides from the tryptic digestion of cyanogen bromide-treated hen egg white lysozyme (HEWL) were isolated by reverse phase high performance liquid chromatography (HPLC) and identified by amino acid analysis. Three peptides containing the I-VIII, II-VII, and III-V + IV-VI disulfide bonds were obtained. The two-disulfide peptide was further digested with proline-specific endopeptidase (PCE) (EC 3.4.21.26). Amino acid analysis of digest peptides separated by HPLC showed four peptides with the IV-VI disulfide bond as well as a peptide with the III-V disulfide bond. The IV-VI peptides were produced by hydrolysis of several alanine-X bonds as well as the prolyl-cystine bond. Our studies show that alanyl peptide bonds to lysyl, seryl, and leucyl residues are susceptible to hydrolysis by PCE preparations, thus substantially extending its known specificity range. The two-disulfide peptide was also digested sequentially with thermolysin and PCE; the resulting IV-VI and III-V peptides were identified by HPLC and amino acid analysis. PCE showed substantial activity at pH 5.3 as well as at pH 8.3. The lower pH is useful in studies of proteins or peptides where base-catalyzed reactions must be limited.
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PMID:Use of proline-specific endopeptidase in the isolation of all four "native" disulfides of hen egg white lysozyme. 390 90

Two patients, a 62-year-old man and a 50-year-old woman, both with deep-seated atypical endothelial tumors within the wide concept of histiocytoid hemangioma, are reported. In case 1, the tumor involved the brachial vein, and, in case 2, a medium-sized vein of the anterior neck. In both cases the involved vein was occluded. Angiography in case 1 suggested a tumor that was enclosed by the same fibrous sheath, the conjunctiva vasorum, that enclosed the occluded vein and its concomitant artery. Both tumors were solid, without conspicuous vascular differentiation by light microscopy. Such differentiation, however, was evident from the electron-microscopic examination, which showed tumor cells with endothelial features forming primitive vascular structures. Positive lectin histochemistry (Ulex Europeus I) and positive immunohistochemistry for factor-VIII-related antigen, actin, and vimentin also gave strong support for the endothelial differentiation of the tumor cells. Immunohistochemical studies of markers for histiocytic (alpha 1-antitrypsin, ferritin, lysozyme), epithelial (cytokeratin, epithelial membrane antigen), and neuroectodermal (S-100 protein) and skeletal muscle (myoglobin) differentiation were negative. At follow-up, after 7 years and 2 years, respectively, there were no signs of local recurrence or metastasis.
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PMID:Atypical hemangioendothelioma of venous origin. A clinicopathologic, angiographic, immunohistochemical, and ultrastructural study of two endothelial tumors within the concept of histiocytoid hemangioma. 393 54

Protamine sulfate reversibly inhibits serum-induced mitogenic stimulation of several nontransformed and neoplastic cell types in vitro. Fifty percent inhibition was induced by approximately 120-150 micrograms protamine sulfate/ml. Cells were affected directly, and inhibition depended on the duration of cell exposure. Heparin, chondroitin sulfate, heparan sulfate, and dextran sulfate neutralized protamine sulfate effects during the early stages of treatment. Nontransformed cells [bovine aortic endothelial cells, adult human gingival fibroblasts (strains 423 and 1101), fetal rat skin (strain 921-K) and muscle fibroblasts] required longer exposure to induce inhibition than did neoplastic cells [rat 3-methylcholanthrene-induced fibrosarcoma cell lines (MCA-6 and MCA-9), a macrophage-like cell line (NCTC-3749), Walker 256 rat carcinoma cells (ATCC-CCL-38), rat Morris hepatoma cells (ATCC-CCL-144), murine melanoma cells (B16), and rat bladder squamous cell carcinoma cells (804-G)]. Other polycationic compounds, including histone type VIII-S, poly-L-lysine, poly-L-arginine, and protamine (free base), were also effective inhibitors, whereas the basic proteins cytochrome c and lysozyme had no effect. Poly-L-histidine, poly-L-glutamic acid, poly-L-aspartic acid, and dextran blue also had no inhibitory effect.
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PMID:Protamine sulfate inhibition of serum-induced mitogenic responses: differential effects on normal and neoplastic cells. 621 Mar 90


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