Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Two derivatives of hen egg-white lysozyme (lysozyme) with single substitutions of a 2,4-dinitrophenyl (DNP) residue were prepared. The reaction of lysozyme with a 10-fold molar excess of 2,4-dinitrobenzene sulfonic acid provided one mono-DNP substituted lysozyme (DNP1-33lysozyme), which was purified by ion-exchange chromatographies. The other one (DNP1-96lysozyme) was prepared as follows. After maleylation of lysozyme in the presence of a 7-fold molar excess of maleic anhydride, the derivative with one free amino group was purified on DE-52. This material was dinitrophenylated with 2,4-dinitrobenzene sulfonic acid and the mono-DNP substituted derivative was purified on DE-52. DNP1-96lysozyme was finally purified on SE-Sephadex C-25, after demaleylation at pH 3.5, at 37 degrees C, for 5 days. DNP1-33lysozyme and DNP1-96lysozyme each migrated as a single band with slower mobility than that of native lysozyme. On reduction, carboxymethylation and chymotrypsin digestion, both mono-DNP substituted lysozymes yielded a single yellow peptide. The amino acid compositions or partial sequence of these peptides indicated that lysine-33 and lysine-96 were the only dinitrophenylated residues in DNP1-33lysozyme and DNP1-96lysozyme, respectively. DNP1-33lysozyme and DNP1-96lysozyme showed antigenic reactivities equal to that of native lysozyme with antisera to lysozyme. The DNP residues on the protein were accessible to anti-DNP antibodies, but the affinities of DNP1-33lysozyme to anti-DNP antibodies were lower than those of DNP1-96lysozyme. This result is discussed with respect to the local environments of the DNP residues in these proteins.
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PMID:Preparations and immunological characterizations of two lysozyme derivatives dinitrophenylated at lysine-33 and lysine-96, respectively. 728 48

Inflammatory cells in lymph nodes of eighteen patients suffering from culture-proven tuberculous lymphadenitis were examined by histological and immunohistochemical techniques. Ten patients suffered from symptomatic HIV-infection and eight patients were immunocompetent individuals without HIV-1 serology. Characteristic granulomas with or without caseation were observed in eight immunocompetent and four HIV-1-infected patients with less marked lymphopenia of CD4 positive peripheral blood lymphocytes. No epitheloid cell formation was present in lymph nodes of HIV1-infected patients with more severe depression of CD4 positive peripheral blood lymphocyte count. Foamy macrophages were found instead of these cells. While many cells--predominantly lymphocytes--express CD25 (IL-2 receptor) in cases with typical epitheloid granulomas there is no such CD25 expression in cases without any epitheloid cell formation. This result suggest that T cell function is necessary for epitheloid granuloma formation in human tuberculosis. The phenotype of macrophages underwent progressive changes parallel to decreasing numbers of CD4 positive peripheral blood lymphocytes. Foamy macrophages in Mycobacterium avium-intracellulare infection represented an end-stage phenotype. They were positive for S100 protein and they did not express lysozyme, alpha-1-anti-chymotrypsin, L1 antigen (Mac387) and CD4, whereas positivity for HLA-DR, CD68 and Ki-M8 was preserved. In situ immunohistochemical demonstration of IFN-alpha, IFN-beta, TNF-alpha, IL-1 and IL-6 revealed that foamy cells in M. tuberculosis infection were highly active effector cells. They contained higher concentrations of the examined cytokines than epitheloid cells in the lesions of HIV+ and HIV-patients. Corresponding to these findings the histological proof of acid-fast bacilli was generally not successful in typical HIV-associated tuberculosis. The foamy appearance may result from the lipid-rich cell membranes of destroyed acid-fast bacilli. In contrast acid-fast bacilli-packed foamy macrophages in AIDS patients with M. avium-intracellulare (MAI) infection did not produce any of the examined cytokines.
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PMID:Immunohistochemical analysis of cell composition and in situ cytokine expression in HIV- and non-HIV-associated tuberculous lymphadenitis. 771 49

The solvation of polar groups at the N-terminal end of alpha-helices was studied by comparing the crystal structures of T4 lysozyme, barley chymotrypsin inhibitor 2 (CI2), barnase and their respective N-cap mutants. Whether or not the N3 residue is solvated on mutating the N-cap Thr/Ser to Ala or Gly appears to be related to the identities and the side-chain conformations of the N2 and N3 residues. When these two residues are alanines, as is in the pseudo-wild-type CI2 (E33A/E34A), the main-chain NH at the N3 position is exposed to the solvent and can be solvated. If the N2 residue is an Asp or a Glu, it is more likely that the side-chain of these residues will form a surrogate N-cap with the amide NH at N3 to compensate for the lost -OH group. In this case, no additional solvation will be observed. In general, Gly can be more stable than Ala at the N-cap because its small side-chain allows nearby polar groups to form hydrogen bonds with optimal geometry with solvent molecules or other polar groups.
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PMID:Stability and solvation of Thr/Ser to Ala and Gly mutations at the N-cap of alpha-helices. 803 23

The percentage of bacteriocin-producing and phage-producing Klebsiella strains was as follows: K. pneumoniae-10%, K. ozaenae-7%, K. rhinoscleromatis-9%. The antimicrobial spectrum of the studied inducible particler was broad and was not limited by the frames of the genus and family. Bacteriocins and bacteriophages from Klebsiella were active to Klebsiella, Enterobacter, Escherichia, Shigella and Proteus representatives significant in medicine. Klebocins and Klebsiella phages exhibited antagonistic effects to phytopathogenic bacteria. Some strains of Erwinia and Pseudomonas were sensitive to phages or bacteriocins from Klebsiella. Bacteriocins protected corn and tomato seeds from contamination by erwinioses agents. All cultures of Agrobacterium, Corynebacterium, Micrococcus, Staphylococcus, Streptococcus were resistant to action of phages and klebocins. Bacteriocins from Klebsiella were assayed for their sensitivity to trypsin, chymotrypsin, lysozyme, ribonuclease, deoxyribonuclease. Action of klebocins was associated with a protein component. Proceeding from data of diffusion through the disc ultrafiltration membranes molecular weight of klebocins was in the range of 30,000 and 50,000 Da.
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PMID:[The antimicrobial spectrum of the action of bacteriocins and bacteriophages from Klebsiella strains]. 816 98

Water sorption isotherms at 27 degrees C have been measured for lysozyme and chymotrypsin in suspensions of toluene, di(n-butyl) ether, n-propanol, and a solution of 1M n-propanol in benzene. Sorption isotherms for the different suspensions are compared by converting solvent water content to the thermodynamic activity of water in each solvent. The sorption behavior is also compared to that for the two proteins hydrated from the vapor phase. At low water activities, all sorption isotherms are similar when compared on the basis of water activity. However, at higher activities, water sorption by the proteins in the organic suspensions is suppressed relative to the sorption of water vapor. The greatest suppression is observed for n-propanol, which suggests that the suppression may be due to a competition for water-binding sites on the protein by the organic solvent. Sorption isotherms at low water activities have also been predicted using a thermodynamic model in which it is assumed that water binds selectively to the ionizable residues on the surface of the protein. A comparison of predicted and measured sorption isotherms shows that the model can provide reasonable estimates of water sorption in nonpolar or moderately polar organic solvent suspensions at low levels of hydration.
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PMID:The hydration of proteins in nearly anhydrous organic solvent suspensions. 836 56

The distribution of the lysosomal enzymes cathepsin B, lysozyme, chymotrypsin, and neutrophil elastase was examined in eccrine, apocrine, and sebaceous glands using a postembedding immunogold labeling procedure. Various amounts of cathepsin B were detected in all glands. Lysozyme, however, was detected in apocrine glands only. The other two lysosomal enzymes were not detectable immunologically. In apocrine and eccrine glands, anti-cathepsin B antibody labeled all secretory granules. In sebaceous glands, only the peripheral layer of cells showed immunological activity for cathepsin B. In apocrine glands, granules containing remnants of cristae were more intensively labeled than those lacking cristae which supports the assumption that both granules are derived from mitochondria by acquiring lysosomal enzymes. The enzymes convert mitochondria to granules with cristae and finally to granules without cristae. Thus the difference in morphology is part of a spectrum of the degradation of mitochondria to granules.
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PMID:Immunelectron microscopic localization of cathepsin B in human exocrine glands. 846 18

The stability changes in peptides and proteins caused by the substitution of a single amino acid, which can be measured experimentally by the change in folding free energy, are evaluated here using effective potentials derived from known protein structures. The analysis is focused on mutations of residues that are accessible to the solvent. These represent in total 106 mutations, introduced at different sites in barnase, bacteriophage T4 lysozyme and chymotrypsin inhibitor 2, and in a synthetic helical peptide. Assuming that the mutations do not modify the backbone structure, the changes in folding free energies are computed using various types of database-derived potentials and are compared with the measured ones. Distance-dependent residue-residue potentials are found to be inadequate for estimating the stability changes caused by these mutations, as they are dominated by hydrophobic interactions, which do not play an essential role at the protein surface. On the contrary, the potentials based on backbone torsion angle propensities yield quite good results. Indeed, for a subset of 96 out of the 106 mutations, the computed and measured changes in folding free energy correlate with a linear correlation coefficient of 0.87. Moreover, the ten mutations that are excluded from the correlation either seem to cause modifications of the backbone structure or to involve strong hydrophobic interactions, which are atypical for solvent-accessible residues. We find furthermore that raising the ionic strength of the solvent used for measuring the changes in folding free energies improves the correlation, as it tends to mask the electrostatic interactions. When adding to these 106 mutations 44 mutations performed in staphylococcal nuclease and chemotactic protein, which were first discarded because some of them were suspected to affect the backbone conformation or the denatured state, the correlation between measured and computed folding free energy changes remains quite good: the correlation coefficient is 0.86 for 135 out of the 150 mutations. The success of the backbone torsion potentials in predicting stability changes indicates that the approximations made for deriving these potentials are adequate. It suggests moreover that the local interactions along the chain dominate at the protein surface.
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PMID:Stability changes upon mutation of solvent-accessible residues in proteins evaluated by database-derived potentials. 863 71

In this study we systematically investigated the cellular distribution, immunohistochemical phenotype, and mucosal disposal function of macrophages in the lamina propria of the human gastrointestinal mucosa (lamina propria macrophages; LPMs). In all tissues examined, most of these LPMs accumulated beneath the epithelial layer that covered the apex of the lamina propria of the mucosa. These cells expressed normal levels of common macrophage markers such as CD68, LN5, lysozyme, ferritin, and alpha 1-anti-chymotrypsin. In addition, they expressed high levels of 25F9 (a market for a certain subpopulation of macrophages), MHC Class II molecules, and CD74 (MHC Class II-associated invariant chain). Interestingly, LPMs possessed some epithelial cell-associated antigens such as cytokeratin, carcinoembryonic antigen (CEA), and Ber-Ep4 in their cytoplasm. Ultrastructurally, these antigens were associated with cellular debris ingested by LPMs, which were recognized as apoptotic fragments by in situ end-labeling. Furthermore, double positive-labeled granules were seen in LPMs by double staining for epithelial cell-associated antigens and in situ end-labeling. These observations suggest that one of the major functions of LPMs is the disposal of apoptotic epithelial cells and that LPMs may be involved in the regulation of mucosal epithelial renewal.
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PMID:Lamina propria macrophages in the human gastrointestinal mucosa: their distribution, immunohistological phenotype, and function. 867 93

A girl, 5.7 years old, gained tolerance to egg white ingestion in spite of high immunoglobulin E (IgE) antibody titers to egg white but retained contact urticaria against egg white. She developed atopic dermatitis on her face at 2 months of age and showed high IgE antibody titers to egg white and cow's milk. Accidental ingestion of egg products initiated immediate symptoms such as wheezing, urticaria, erythema and edema of the eyelids and conjunctiva three times. These symptoms were confirmed by challenge tests using boiled egg white at 3.9 years of age. She also reacted positively to a 20 min patch test on her volar arm with raw egg white. However, there were no reactions to the oral challenge test by boiled egg and freeze-dried egg white at 5.1 and 5.7 years of age, respectively. This non-responsiveness was confirmed by a double-blind, placebo-controlled food challenge using freeze-dried egg white. Nevertheless, she showed positive reactions to a 20 min patch test with freeze-dried egg white. Her IgE antibody titers to the egg white components including ovomucoid, ovalbumin, ovotransferrin and lysozyme as well as egg white were high from 2.9 to 5.7 years old. Her IgE antibody titers for the ovomucoid fragments digested by pepsin, chymotrypsin and trypsin were not lower than those of positive control subjects. The binding activity of IgE antibody to ovomucoid, however, decreased from 2.9 to 5.6 years as shown by radioallergosorbent test (RAST) inhibition assays. The IgE antibody showed weaker binding activity to pepsin- and chymotrypsin-digested ovomucoid that were filtered through cut-off 10,000 filter at the age of 2.1 and 5.7 years. We speculated that the maturation of secretion of digestive enzymes was involved in the mechanisms of the acquisition of tolerance to egg white ingestion in spite of the persistence of contact urticaria.
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PMID:A case retaining contact urticaria against egg white after gaining tolerance to ingestion. 912 58

Spectroscopic techniques (UV absorbance, circular dichroism, fluorescence emission and anisotropy, and light scattering) were used to investigate enzyme solubilization in Aerosol-OT (AOT) reversed micelles in which a bile salt, sodium taurocholate (NaTC), is used as a novel cosurfactant. NaTC significantly increases the water capacity and size of the reversed micelles through surfactant reorganization. The solubilization of several enzymes, including lysozyme, chymotrypsin, lipase, lipoxidase, carbonic anhydrase, and ribonuclease A, was demonstrated. These enzymes, ranging in mass from 10(4) to 10(5) Da, are incorporated in the micelles in stable, optically transparent solutions. Several other proteins were not successfully solubilized. The presence of NaTC in the reversed micelles significantly altered the conformations of the solubilized enzymes, apparently by promoting unfolding of the enzyme through interactions with the interior micellar interface. Lysozyme and lipase respond to solubilization in the AOT/NaTC micelles by altering their conformations to accommodate the micellar structure. The effect of NaTC is greatest for lysozyme, inducing a higher degree of order and helicity in the enzyme structure. Chymotrypsin, on the other hand, disrupts the micellar structure and reorganizes the surfactants to accommodate its own preferred conformation. Addition of NaTC to the reversed micelles causes a 3-fold increase in the enzymatic activity of solubilized chymotrypsin. Copyright 1997Academic Press
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PMID:Enzyme Solubilization in a Reversed Micellar Microreactor with a Bile Salt Cosurfactant 929 86


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