Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lysozyme activity of 403 strains of lactobacilli were investigated; of these 26 were from foreign sets and 377 were isolated from the contents of the stomach, feces and vaginal discharge of healthy adults. The species reference of lactobacillae was confirmed by the results of study of their physiologo-biochemical properties with the aid of 45 tests. A method of agar plates was adapted to determination of lysozyme: the autoclaved suspension of Micrococcus lysodeikticus (strain No. 2665) was added to the agar medium MPC-I, and lactobacilli were cultivated for 4 days in the CO2 atmosphere at 37 degrees C. There was revealed the capacity of L. fermenti and L. brevis to produce lysozyme; in L. fermenti the lysozyme activity was much more frequent (p less than 0.001); strains of the rest of the species of lactobacilli differentiated by the Rogosa and Sharpe's classification proved to be lysozyme-negative. It was shown that the lactobacilli of the L. fermenti species, included into the microflora of the intestine and the vagina of healthy adults as a rule possessed lysozyme activity. L. fermenti strain 90T-S4 used in the production of dry lactobacterin also produced lysozyme. All this favours an important role of L. fermenti in the protective function of the microflora.
 ...
PMID:[Ability of lactobacilli in the human microflora to produce lysozyme]. 81 10

We report the generation of macrophage-hybridomas, obtained by somatic cell fusion between macrophage-enriched C3H.eB spleen cell population, and a drug-resistant MPC-11 myeloma cell line, designated as 4T00.1L1 clone. Screening for hybridomas possessing macrophage properties was carried out by assaying the presence of two macrophage-specific enzymes: lysozyme and nonspecific esterase. Two hybridomas, E2-7 and E2-10, were selected for further studies. We found that clones of E2-7 (E2-7.7) did not express Fc receptors but possessed cell-surface Ia molecules. In contrast, clones of E2-10 (E2-10.20) possessed Fc receptors but were devoid of Ia molecules. E2-7.7 did, however, express Fc receptors after mitomycin treatment, whereas E2-10.20 eliminated the expression of Fc receptors after treatment with mitomycin C. Opsonized erythrocytes were phagocytized by E2-10.20 cells, but not by E2-7.7. Phagocytosis was thus correlated with the possession of Fc receptors. Testing the response of KLH-primed lymph node cells to KLH-pulsed hybridoma cells, we found that E2-7.7 cells caused antigen-specific lymphoproliferative response, whereas E2-10.20 did not. Thus, antigens could be presented by E2-7.7 but not by E2-10.20 cells. The response was shown to be mediated by T but not by B lymphocytes. The difference in antigen-presenting capacity could not be attributed to differences in antigen uptake by the different hybridomas, because the two hybridomas manifested the same level of pinocytosis. Both hybridomas produced IL1. The differences in the properties of the two hybridomas may indicate that the normal partners represent two distinct subpopulations of macrophages. The segregation of functional properties among the hybridoma clones may lead to a clarification of the dependence of distinct functions on defined molecular structures.
 ...
PMID:Macrophage-hybridomas: generation, structure, and function. 660 46

The multicatalytic proteinase complex (MPC, proteasome) is assembled from 14 nonidentical protein subunits. It expresses five distinct proteolytic activities, including a chymotrypsin-like activity, cleaving after hydrophobic residues, and a branched chain amino acid-preferring component (BrAAP), cleaving preferentially after branched chain residues. Exposure of cells to interferons leads to replacement of the X, Y, and Z subunits by the LMP2, LMP7, and MECL1 subunits. This "immunoproteasome" is critical to processing of certain antigens. The enzymatic basis for enhanced antigen processing has not been determined. To gain insight into this question, we examined sites and relative rates of cleavage of bonds in denatured, reduced, carboxyamidomethylated lysozyme, a 129-amino acid protein, by MPC from bovine spleen, in which the X, Y, and Z subunits are replaced by LMP2, LMP7, and MECL1. We compared cleavages to those catalyzed by MPC from bovine pituitary, which contains only the X, Y, and Z subunits. We found marked increases in the rates and number of cleavages after branched chain residues in reduced, carboxyamidomethylated lysozyme by the spleen MPC. This was largely due to accelerated cleavages of bonds after a Phi-X-Br motif, where Phi is a hydrophobic residue, X is a small neutral or polar residue, and Br is a branched chain residue. Inhibitors with these structural properties were selective and potent inhibitors of the BrAAP activity of the spleen MPC. The above findings indicate that alterations in activity and substrate specificity of the BrAAP activity are important factors underlying the altered cleavages after hydrophobic residues associated with incorporation of interferon-inducible subunits. The potential relevance of the findings to antigen processing functions of MPC is discussed.
 ...
PMID:Altered properties of the branched chain amino acid-preferring activity contribute to increased cleavages after branched chain residues by the "immunoproteasome". 964 32

The multicatalytic proteinase complex (MPC, proteasome) is composed of 28 subunits organized into four rings surrounding a water-filled canal. The catalytic centers face the inner canal confining protein substrates to an enclosed space. Experimental findings obtained with MPC from archaebacteria suggest that degradation of proteins by the complex is processive and have led to the proposal that the lengths of the peptides formed during degradation depend on the distances between active sites in the catalytic chamber. To test whether these postulates are valid for the MPC from a higher organism, we examined the size distributions of products formed early versus late in the course of protein degradation using reduced carboxamidomethylated lysozyme (RCM-lysozyme) and MPC from bovine spleen and pituitary. The majority of final degradation products ranged in length from 6 to 20 amino acids without a clear predilection for peptides of a particular, uniform size. Our observations suggest that selection of cleavage sites is governed by the amino acid sequence specificity of the MPC catalytic sites rather than the distances between the active sites. Early in the course of degradation, peptides with masses between 5 and 10 kDa accumulated in more than 80-fold molar excess over the MPC, indicating dissociation of large, partially degraded intermediates. Initial cleavages occurred at distances between 10 and 44 amino acids from the N- or C-terminus of the molecule and often involved removal of a fragment from both the N- and C-termini of RCM-lysozyme. Our data indicate that degradation of proteins by MPCs from higher organisms involves a nonprocessive mechanism comprised of multiple, independent cleavages with dissociation of degradation intermediates. A general model for protein degradation by the MPC is discussed.
 ...
PMID:Lysozyme degradation by the bovine multicatalytic proteinase complex (proteasome): evidence for a nonprocessive mode of degradation. 1054 80

Surfaces based on grafted poly(2-methacryloyloxyethyl phosphorylcholine) (poly(MPC)) "brushes" with a constant graft density of 0.39 chain/nm2 and chain length from 5 to 200 monomer units were prepared by surface-initiated atom transfer radical polymerization (ATRP) on silicon wafers. The chain length and layer thickness of the poly(MPC) grafts were varied via the ratio of MPC to sacrificial initiator. The surfaces were characterized by water contact angle, XPS, and AFM. The effect of poly(MPC) chain length on fibrinogen and lysozyme adsorption was studied in TBS buffer at pH 7.4. The adsorption of both proteins on the poly(MPC)-grafted surfaces was greatly reduced compared to the unmodified silicon. Adsorption decreased with increasing chain length of the poly(MPC) grafts. Grafts of chain length 200 (MW 59 000) gave adsorption levels of 7 and 2 ng/cm2, respectively, for fibrinogen and lysozyme at 1 mg/mL protein concentration, corresponding to reductions of greater than 98% compared to the unmodified silicon. Adsorption experiments using mixtures of the two proteins showed that the suppression of protein adsorption on the poly(MPC)-grafted surfaces was not strongly dependent on protein size or charge.
 ...
PMID:Adsorption of fibrinogen and lysozyme on silicon grafted with poly(2-methacryloyloxyethyl phosphorylcholine) via surface-initiated atom transfer radical polymerization. 1595 50

The objective of this work was to compare poly(ethylene glycol) (PEG) and phosphorylcholine (PC) moieties as surface modifiers with respect to their ability to inhibit protein adsorption. Surfaces were prepared by graft polymerization of the methacrylate monomers oligo(ethylene glycol) methyl ether methacrylate (OEGMA, MW 300, PEG side chains of length n=4.5) and 2-methacryloyloxyethyl phosphorylcholine (MPC, MW 295). The grafted polymers thus contained short PEG chains and PC, respectively, as side groups. Grafting on silicon was carried out using surface-initiated atom transfer radical polymerization (ATRP). Graft density was controlled via the surface density of the ATRP initiator, and chain length of the grafts was controlled via the ratio of monomer to sacrificial initiator. The grafted surfaces were characterized by water contact angle, x-ray photoelectron spectroscopy, and atomic force microscopy. The effect of graft density and chain length on fibrinogen adsorption from buffer was investigated using radio labeling methods. Adsorption to both MPC- and OEGMA-grafted surfaces was found to decrease with increasing graft density and chain length. Adsorption on the MPC and OEGMA surfaces for a given chain length and density was essentially the same. Very low adsorption levels of the order of 7 ngcm(2) were seen on the most resistant surfaces. The effect of protein size on resistance to adsorption was studied using binary solutions of lysozyme (MW 14 600) and fibrinogen (MW 340 000). Adsorption levels in these experiments were also greatly reduced on the grafted surfaces compared to the control surfaces. It was concluded that at the lowest graft density, both proteins had unrestricted access to the substrate, and the relative affinities of the proteins for the substrate (higher affinity of fibrinogen) determined the composition of the layer. At the highest graft density also, where the adsorption of both proteins was very low, no preference for one or the other protein was evident, suggesting that adsorption did not involve penetration of the grafts and was occurring at the outer surface of the graft layer. It thus seems likely that preference among different proteins based on ability to penetrate the graft layer would occur, if at all, at a grafting density intermediate between 0.1 and 0.39 cm(2). Again the MPC and OEGMA surfaces behaved similarly. It is suggested that the main determinant of the protein resistance of these surfaces is the "water barrier layer" resulting from their hydrophilic character. In turn the efficacy of the water barrier depends on the monomer density in the graft layer.
 ...
PMID:Protein resistant surfaces: comparison of acrylate graft polymers bearing oligo-ethylene oxide and phosphorylcholine side chains. 2040 15

Poly(2-methacryloyloxyethyl phosphorylcholine) (poly(MPC)) was grafted from various polymeric substrates to prepare protein-resistant materials. The poly(MPC) chain length was adjusted via the ratio of monomer to sacrificial initiator in solution. The surfaces were characterized by water contact angle and X-ray photoelectron spectroscopy (XPS). The protein-resistant properties of the poly(MPC)-grafted surfaces were evaluated by single adsorption experiments with fibrinogen and lysozyme. It was shown that the simple three-step grafting method could be applied to modify various biomaterial surfaces including polyurethane and silicones. The adsorption of fibrinogen and lysozyme to the modified surfaces was greatly reduced compared to the unmodified surfaces, and adsorption decreased with increasing poly(MPC) chain length. On polyurethane film grafted with poly(MPC) of chain length 100, the reduction in adsorption was approx. 96% for lysozyme and approx. 99% for fibrinogen.
 ...
PMID:Protein-resistant materials via surface-initiated atom transfer radical polymerization of 2-methacryloyloxyethyl phosphorylcholine. 2053 88

Poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC), when end-tethered to surfaces by the adsorption of copolymeric cationic segments, forms adsorbed layers that substantially reduce protein adsorption. This study examined variations in the molecular architecture of copolymers containing cationic poly(trimethylammonium ethyl methacrylate (pTMAEMA) anchor blocks that adsorbed strongly to negative surfaces. With appropriate copolymer design, the pTMAEMA blocks were shielded, by pMPC tethers, from solution-phase proteins. The most protein-resistant copolymer layers, eliminating fibrinogen and lysozyme adsorption within detectible limits of 0.01 mg/m2, had metrics (the amount of pMPC at the surface and the reduced tether footprint) consistent with the formation of an interfacial polymer brush. The p(TMAEMA-b-MPC) copolymer layers substantially outperformed the protein resistance of surface-polymerized pMPC layers when compared on a per-polyzwitterion-mass basis or on the basis of the scaled tether area. Additionally, p(TMAEMA-b-MPC) copolymer layers offered advantages over the much-studied cationically anchored poly(ethylene glycol) (PEG) graft copolymer system, which forms PEG brushes by the adsorption of a poly l-lysine (PLL) backbone. Although the optimized p(TMAEMA-b-MPC) and PLL-PEG copolymers were similarly fibrinogen-resistant, the cationic protein lysozyme was repelled by pMPC but adhered to the PEG brush via PEG-lysozyme attractions. Additionally, the adsorbed p(TMAEMA-b-MPC) copolymers were not displaced by poly l-lysine homopolymers, which completely displaced the PLL-PEG copolymer to expose a protein-adhesive surface. Thus, the p(TMAEMA-b-MPC) copolymer system comprises a scalable means to produce protein-repellent surfaces, free of the complexities of surface-initiated polymerization and with the advantages of polyzwitterions.
 ...
PMID:Adsorbed Polyzwitterion Copolymer Layers Designed for Protein Repellency and Interfacial Retention. 2913 1

A series of hydrogels with intrinsic antifouling properties was prepared via surface-functionalization of poly(2-hydroxyethyl methacrylate) [p(HEMA)]-based hydrogels with the biomembrane-mimicking zwitterionic polymer, poly(2-methacryloyloxyethyl phosphorylcholine) [p(MPC)]. The p(MPC)-modified hydrogels have enhanced surface wettability, high water content retention (61.0%-68.3%), and good transmittance (>90%). Notably, the presence of zwitterionic MPC moieties at the hydrogel surfaces lowered the adsorption of proteins such as lysozyme and bovine serum albumin (BSA) by 73%-74% and 59%-66%, respectively, and reduced bacterial adsorption by approximately 10%-73% relative to the unmodified control. The anti-biofouling properties of the p(MPC)-functionalized hydrogels are largely attributed to the dense hydration layer formed at the hydrogel surfaces by the zwitterionic moieties. Overall, the results demonstrate that biocompatible and antifouling hydrogels based on p(HEMA)-p(MPC) structures have promising potential for application in biomedical materials.
 ...
PMID:Development of Poly(2-Methacryloyloxyethyl Phosphorylcholine)-Functionalized Hydrogels for Reducing Protein and Bacterial Adsorption. 3209 41