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)

A method was devised to isolate N-terminal peptide fragments from the polypeptide chains constituting thyroglobulin even in the case when the terminal amino groups are naturally blocked, for instance, acylated. Reduced and carboxymethylated hog thyroglobulin was first acetylated and digested with thermolysin. The blocked N-terminal peptide fragments were separated from the unblocked N-terminal fragments by column chromatography on Dowex 50, then on Dowex 1 after dinitrophenylation, and finally fractionated into ten fractions by paper chromatography after gel filtration on Sephadex G-10. Structural analyses by enzymic or partial acid hydrolysis of these peptide fractions failed to detect N-terminal acetyl amino acid. Instead, pyroglutamyl peptides including pyroglutamylleucine were found. By the same method, acetylated lysine and glycine were identified for chicken lysozyme and horse myoglobin, respectively. The use of thermolysin because of its unique specificity, and the possible relevance of the present result to the previous data on the N-terminal analysis of thyroglobulin are discussed.
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PMID:The presence of N-terminal pyroglutamyl residues in hog thyroglobulin. 93 62

By display of antibody repertoires on the surface of a filamentous bacteriophage and selection of the phage by binding to antigen, we can mimic immune selection. Recently, by tapping the repertoire of rearranged V-genes from the peripheral blood lymphocytes of unimmunised donors, we succeeded in making human antibody fragments with different specificities, including both haptens and proteins, from the same library of phage. Now we have built a repertoire of human VH genes from 49 human germline VH gene segments rearranged in vitro to create a synthetic third complementarity determining region (CDR) of five or eight residues. The rearranged VH genes were cloned with a human V lambda 3 light chain as single chain Fv fragments for phage display, and the library of phage panned by binding to each of two haptens, 2-phenyl-5-oxazolone (phOx) or 3-iodo-4-hydroxy-5-nitrophenyl-acetate (NIP) coupled to bovine serum albumin (BSA). Many different antibody fragments were isolated which bound specifically to hapten, some with affinities in the micromolar range. The in vitro "immune response" to the hapten NIP was dominated by the 9-1 segment (VH3 family), and that to phOx by the VH26 segment (VH3 family) with an invariant aromatic residue (Tyr, Phe, Trp) at residue 97 of CDR3. However, the isolation of phage against protein antigens proved more elusive, with a single phage binding to human tumour necrosis factor, and none to bovine serum albumin, turkey egg-white lysozyme or human thyroglobulin. Nevertheless, the work shows that human antibody fragments with specific binding activities can be made entirely in vitro.
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PMID:By-passing immunisation. Human antibodies from synthetic repertoires of germline VH gene segments rearranged in vitro. 140 59

The relative susceptibilities of lenticular proteins (alpha, beta and gamma-crystallins) and a number of proteins of non-lenticular origin, to hydroxyl radical-mediated peptide bond cleavage were compared. The non-lenticular proteins (bovine serum albumin, ovalbumin, alcohol dehydrogenase, lysozyme, thyroglobulin, beta-amylase, haemoglobin and carbonic anhydrase) were readily cleaved into acid-soluble fragments following 5 hours treatment with copper ions and hydrogen peroxide. In contrast the crystallins were almost totally unaffected by similar treatment. When alpha-crystallin was pre-treated with acid or cleaved into large fragments with cyanogen bromide it became susceptible to hydroxyl radical attack, yet heating the protein did not diminish its resistance. It is suggested that the resistance of alpha-crystallin to the copper/peroxide-mediated fragmentation may be dependent on the conformation of the protein.
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PMID:Differences in susceptibility between crystallins and non-lenticular proteins to copper and H2O2-mediated peptide bond cleavage. 175 88

The cellular sediments of 42 malignant and 16 benign effusions (58 cases) were studied using the immunoperoxidase technique. Serial sections of formalin-fixed, paraffin-embedded residual sediments of effusions, sent for routine cytologic examination, were studied by commercially available polyclonal antisera against lysozyme, alpha 1-anti-trypsin, alpha 1-anti-chymotrypsin, tissue polypeptide antigen (TPA), a wide-spectrum anti-keratin, carcinoembryonic antigen (CEA) and, in single cases, thyroglobulin and prostate-specific antigen. A final definite diagnosis from histologic study of biopsy or autopsy specimens was known in all cases. All carcinomas, the mesotheliomas and the reactive mesothelial cells showed a positive reaction for TPA and, partly, the wide-spectrum keratin. Lysozyme could be demonstrated in the cells of the one proven malignant fibrous histiocytoma; all malignant epithelial cells were negative. Alpha 1-anti-chymotrypsin and alpha 1-anti-trypsin showed similar reactions: they were often positive in carcinoma cells of the breast, the bronchial system and the pancreas, in contrast to a mostly negative reaction in carcinomas of the stomach and ovary. CEA showed considerable differences; it was always negative in benign and malignant mesothelial proliferations but mostly positive in carcinomas of the stomach, pancreas and bronchial system. It was only positive in less than 20% of the carcinomas of the breast and always negative in the proven malignant effusions of primary carcinomas of the ovary and prostate. Studying a combination of several tumor markers is possible in serial paraffin-embedded sections and may be a valuable criterion in the cytologic diagnosis of effusions.
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PMID:Immunohistochemical study of lysozyme, alpha 1-anti-chymotrypsin, tissue polypeptide antigen, keratin and carcinoembryonic antigen in effusion sediments. 243 1

The immunoperoxidase method was modified and adapted for use on cells obtained by fine-needle aspiration biopsy for routine diagnostic cytology. Combinations of different modes of fixation and graded trypsinization were tested. Best results were obtained with fixation in formol-acetone followed by enzyme digestion for 3-6 min; exact times were adjusted for the individual antigen. With optimal conditions as to fixation and proteolytic digestion, the method was found to be sensitive and reproducible and without artifactual background staining. Various intracytoplasmic antigens of diagnostic importance such as immunoglobulins, prostate-specific antigen, keratin, thyroglobulin, S-100, alpha-1-antitrypsin, and lysozyme in lymphoid cells, bone marrow cells, and tumor cells of epithelial and mesenchymal origin were detected. Staining of newly prepared or up to 2-yr-old specimens gave equally good results. Both cellular morphology and the results of immunoperoxidase staining can be studied simultaneously. The method is considered valuable for increasing accuracy of diagnostic cytology.
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PMID:Methodological aspects and application of the immunoperoxidase staining technique in diagnostic fine-needle aspiration cytology. 355 19

Twenty-four cases of subacute thyroiditis were examined immunohistochemically and ultrastructurally, with special attention being directed to the multinucleated giant cells that characterize the lesions of this condition. Immunohistochemical study revealed that 99 per cent of the giant cells contained lysozyme, 82 per cent contained vimentin, 66 per cent contained alpha 1-antitrypsin, and 61 per cent contained thyroxine. Only 17 per cent contained thyroglobulin, 5 per cent contained keratin, 16 per cent contained epithelial membrane antigen, and 4 per cent contained leukocyte common antigen. Mononuclear cells infiltrating the follicular spaces showed a staining pattern similar to that of the multinucleated giant cells. Desquamated follicular epithelial cells were strongly positive for thyroglobulin and thyroxine, while regenerated epithelia that formed small follicles were positive for thyroglobulin but negative for thyroxine. Electron microscopic examination of cell ultrastructure revealed that most multinucleated giant cells had structures identical with those of infiltrating mononuclear cells, particularly with histiocytes, and that giant cells were formed by mononuclear cell fusion. These findings indicate the majority of multinucleated giant cells in subacute thyroiditis are derived from mononuclear-histiocyte cells.
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PMID:Immunohistochemical and ultrastructural study of subacute thyroiditis, with special reference to multinucleated giant cells. 362 52

A method has been developed for measuring the adhesion of platelets to purified collagen fibers obtained from bovine tendon. This method differs from others in that: (a) platelet adhesion is measured in the absence of platelet aggregation; (b) platelet-rich plasma collected in ACD (acid citrate dextrose) or EDTA, or washed platelets can be employed; (c) adherent platelets are enumerated directly; (d) erythrocytes and leukocytes do not adhere. Washed platelets suspended in human Ringer solution exhibit negligible adhesion (at the platelet concentrations employed) in contrast to washed platelets suspended in plasma. Addition of purified human fibrinogen (95% clottable, 2-4 mg/ml) to human Ringer solution completely restores the ability of washed platelets to adhere to collagen fibers. Albumin (fatty acid free, 50 mg/ml) is also capable of restoring adhesion. Albumin and seven other proteins at concentrations of 5-10 mg/ml, with varying molecular weights, isoelectric points, and frictional coefficients are incapable of supporting the adhesion of washed platelets. The proteins tested were human globulin, hexokinase, hemoglobin, cytochrome-C, insulin, thyroglobulin, and muramidase. Platelet adhesion is proportional to both platelet concentration and fibrinogen concentration, but is independent of temperature or glycogen stores. Modification of fibrinogen by acylation of amino groups or removal of sialic acid has no effect on its ability to support platelet adhesion. Degradation of fibrinogen with purified plasmin results in decreased support of platelet adhesion. This accompanied formation of early breakdown products with clottability ranging from 84-0%. Formation of fibrinogen degradation products was monitored by SDS-polyacrylamide gel electrophoresis of the corresponding fibrins after reduction of disulfide bonds (a method capable of distinguishing alpha-, beta- and gamma-chains). Decreased support of platelet adhesion is associated with the disappearance of intact alpha- chains and early modification of the beta-chains. Purified proteinpolysaccharide macromolecules obtained from bovine nasal and humeral cartilage, and from nucleosus pulposus are as effective as fibrinogen on a weight basis and ten to thirty times more effective on a molar basis in supporting platelet adhesion. The purified mucopolysaccharide side chains: chondroitin-4-sulfate, chondroitin-6-sulfate, and keratan-sulfate are incapable of supporting platelet adhesion.
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PMID:Biochemical and biophysical aspects of human platelet adhesion to collagen fibers. 556 92

Colchicine fluoresces when bound to tubulin but not in water, dioxane, or benzene. The basis of the fluorescence has now been investigated. Colchicine fluoresces in higher alcohols and shows a blue shift as a function of chain length. Glycerol produces a higher fluorescence efficiency and a further blue shift. Plots of 1/fluorescence versus T/eta yield straight lines for both alcohols and glycerol/water mixtures. Fluorescence in glycerol/dimethyl sulfoxide mixtures, in which the dielectric constant remains unchanged, varies as a function of solvent viscosity. Even highly nonpolar solvents such as dioxane require a threshold viscosity for fluorescence to occur. When solvent polarity was decreased at constant viscosity, there was also an enhancement of colchicine fluorescence, but this effect appeared to be smaller than that obtained with increasing viscosity. Immobilization by covalent attachment of desacetylcolchicine to thyroglobulin, serum albumin, or lysozyme also promotes fluorescence from the drug. By contrast, the highly rigid analogue of colchicine, imerubine, fluoresces in water and is unaffected by viscosity changes. We concluded that a major contribution to colchicine fluorescence stems from immobilization of colchicine in the site and that this response to immobilization depends, in part, on the partially flexible nature of the drug. Since certain other flexible molecules such as auramine O, reduced flavines, and diarylalkanes also require increased viscosity or binding to macromolecules to fluoresce at room temperature, we propose that immobilization-enhanced fluorescence may be more common than heretofore believed.
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PMID:Immobilization-dependent fluorescence of colchicine. 648 May 86

In chickens, single functional immunoglobulin variable and joining gene segments at each of the heavy and light chain loci undergo V(D)J rearrangement. Diversity is subsequently introduced by conversions templated by upstream pseudo V region genes in such a way that practically all V regions in mature B cells have identical ends. This greatly simplifies the representative amplification of V region genes. Furthermore, the entire naive repertoire of the adult chicken is produced in the bursa of Fabricius of the young bird. These special properties of the generation of immunoglobulin diversity in chickens have been exploited in the development of procedures to produce large libraries of diverse antibody combining sites derived from chicken Ig genes and expressed on filamentous bacteriophage. The utility of this library was assessed by selection of specifically binding phage using three solid phase-bound protein antigens, hen egg white lysozyme, bovine thyroglobulin and bovine serum albumin. The sequences of the V region genes thus isolated demonstrated that selection was specific and that the library contained useful diversity of binding sites. This library provides access to a repertoire whose diversity is based on a mechanism different from that underlying previously available libraries. The demonstrated feasibility of generating chicken phage antibodies may lead to the production of monoclonal reagents from immunised chickens, and the derivation of reagents for studying immunoglobulin mediated selection in avian B cell development.
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PMID:Selection of specific phage-display antibodies using libraries derived from chicken immunoglobulin genes. 756 Nov 41

The major proteins in the lumen of the endoplasmic reticulum (ER) are thought to function in Ca2+ sequestration or as "molecular chaperones" in the folding and assembly of membrane or secreted proteins. Based on the ability of many chaperones to bind selectively to unfolded proteins and to dissociate from them upon ATP hydrolysis, we developed an affinity chromatography method to isolate proteins with these characteristics from pancreatic or liver ER. Seven ER proteins bound selectively to denatured protein columns and were specifically eluted by ATP (10(-6) M) but not by a nonhydrolyzable ATP analog. These proteins were identified with antibodies and microsequencing as the ER chaperone BiP (grp78), grp94, calreticulin, a novel 46-kDa protein that binds azido-ATP, as well as three members of the thioredoxin superfamily: protein-disulfide isomerase, ERp72, and a previously reported 50-kDa protein (p50). This set of seven proteins bound to and was eluted with ATP from a variety of denatured proteins, including histone, gelatin, alpha fetoprotein, thyroglobulin, lysozyme, casein, and IgG. The release of grp94, protein-disulfide isomerase, ERp72, calreticulin, and p50 was stimulated by Ca2+ in the presence of ATP. These proteins thus appear to function as Ca(2+)-dependent chaperones, which may account for the Ca2+ and ATP requirement for protein folding in the ER.
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PMID:A set of endoplasmic reticulum proteins possessing properties of molecular chaperones includes Ca(2+)-binding proteins and members of the thioredoxin superfamily. 829 23


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