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)

Application of proteins and peptides as human therapeutics is expanding rapidly as drug discovery becomes more prevalent. Conjugation of polymers to proteins can circumvent many problems and pegylation of proteins is now emerging as acceptable practice. This paper describes the synthesis of alpha-aldehyde-terminated poly(methoxyPEG)methacrylates from Cu(I) mediated living radical polymerization (Mn = 11 000, 22 000 and 32 000; PDi < 1.15), and their efficient conjugation to lysozyme, as a model protein. This offers an attractive and flexible alternative to linear poly(ethylene glycol) opening up the possibility of using the full power of living radical polymerization.
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PMID:Alpha-aldehyde terminally functional methacrylic polymers from living radical polymerization: application in protein conjugation "pegylation". 1547 65

In an effort to develop potent anti-inflammatory and cancer chemopreventive agents, a series of chalcones were prepared by Claisen-Schmidt condensation of appropriate acetophenones with suitable aromatic aldehyde or prepared with appropriate dihydrochalcone reacted with appropriate alkyl bromide or prepared in one-pot procedure involving acetophenone and convenient aromatic aldehyde using ultrasonic agitation on basic alumina. The synthesized products were tested for their inhibitory effects on the activation of mast cells, neutrophils, macrophages, and microglial cells. The potent inhibitors of NO production in macrophages and microglial cells were further evaluated for their in vitro cytotoxic effects against several human cancer cell lines. 2'-Hydroxychalcones 1-3, and 2',5'-dihydroxychalcone 7 exhibited potent inhibitory effects on the release of beta-glucuronidase or lysozyme from rat neutrophils stimulated with formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB). Two 2'-hydroxychalcones (1 and 3) showed potent inhibitory effects on superoxide anion generation in rat neutrophils in response to fMLP/CB. The previously reported chalcone, 5, 6, and 12, exhibited potent inhibitory effect on NO production in lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma)-activated N9 microglial cells or in LPS-activated RAW 264.7 macrophage-like cells. The potent inhibitors 5, 6, and 12 of NO production in macrophages or microglial cells revealed significant or marginal cytotoxic effects against several human cancer lines. Compound 12 manifested potent selective cytotoxicity against human MCF-7 cells and caused cell death by apoptosis. The present results demonstrated that 1-3, and 7 have anti-inflammatory effects and 5, 6, and 12 are potential anti-inflammatory and cancer chemopreventive agents.
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PMID:Synthetic chalcones as potential anti-inflammatory and cancer chemopreventive agents. 1564 15

A theoretical DFT(B3LYP) investigation of the catalytic cycle of lysozyme has provided further evidence for a mechanism involving a glycosil-enzyme covalent intermediate, in agreement with recent experimental data. This type of intermediate has been located along two different pathways. Along the favored path the retention of the anomeric configuration of the peptidoglycan NAM unit involved in the reaction, is the result of two subsequent inversions at the C(1) carbon. The other path involves the opening of the pyranose ring and a nucleophilic attack on the prochiral carbonyl group of the open aldehyde, restoring the original anomeric configuration. No evidence has been found for a pathway characterized by the formation of an oxocarbenium ion (stabilized by resonance and electrostatic interactions), as suggested in the most popular mechanistic schemes.
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PMID:A theoretical DFT investigation of the lysozyme mechanism: computational evidence for a covalent intermediate pathway. 1568 46

Grafting of poly(ethylene glycol) (PEG) is a common strategy for reducing nonspecific interactions of surfaces with proteins. We have used grafting at "cloud point" solution conditions that ensures maximum grafting density of linear methoxy terminated PEG-aldehyde (mPEG-ald, M(w) = 5000 and 30000). In an alternative approach, surfaces were modified with layers prepared from isocyanate terminated, star shaped poly(ethylene glycol-stat-propylene glycol) prepolymers (80% ethylene glycol, six arms, M(w) = 3000, 12,000, and 18,000; this compound will be referred to as "Star PEG" in the text). Due to the highly reactive endgroups, these molecules form a dense network on the substrate with a high polymer surface coverage. The two systems were compared regarding their ability to prevent unspecific adsorption of insulin and lysozyme. The layers were analyzed by ellipsometry, contact angle measurements, and XPS. Protein adsorption was monitored by surface MALDI-TOF MS and fluorescence microscopy. No protein adsorption could be detected on Star PEG coatings and on mPEG-ald 5000, whereas mPEG-ald 30,000 could only prevent adsorption of lysozyme but not of the smaller insulin.
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PMID:Comparison of coatings from reactive star shaped PEG-stat-PPG prepolymers and grafted linear PEG for biological and medical applications. 1576 65

To design artificial proteases that cleave peptide backbones of a wide range of proteins at selected sites, artificial active sites comprising the Cu(II) complex of cyclen (Cu(II)Cyc) and aldehyde group were synthesized on a cross-linked polystyrene. The aldehyde group was employed as the binding site in view of its ability of reversible formation of imine bonds with epsilon-amino groups of Lys residues exposed on the surface of proteins and Cu(II)Cyc as the catalytic group for peptide hydrolysis. The two polymeric artificial metalloproteases synthesized in the present study cleaved all of the protein substrates examined (myoglobin, gamma-globulin, bovine serum albumin, human serum albumin, lysozyme, and ovalbumin), manifesting saturation kinetic behavior. At 50 degrees C and pH 9.0 or 9.5, K(m) was (1.3-22) x 10(-)(4) M, comparable to those of natural proteases, and k(cat) was (6.0-25) x 10(-)(4) s(-)(1), corresponding to half-lives of 4.6-19 min. Intermediacy of the imine complexes formed between the aldehyde group of the catalyst and the epsilon-amino groups of Lys residues of the substrates was confirmed by the trapping experiment with NaB(OAc)(3)H. MALDI-TOF MS of the proteolytic reaction mixtures revealed formation of various cleavage products. Structures of some of the cleavage products were determined by using carboxypeptidase A and trypsin. Among various cleavage sites thus identified, Gln(91)-Ser(92) and Ala(94)-Thr(95) were the major initial cleavage sites in the degradation of myoglobin by the two catalysts. The selective cleavage of Gln(91)-Ser(92) and Ala(94)-Thr(95) was attributed to general acid assistance in peptide cleavage by Tyr(146) located in proximity to the two peptide bonds. Broad substrate selectivity, high cleavage-site selectivity, and high proteolytic rate are achieved, therefore, by positioning the aldehyde group in proximity to Cu(II)Cyc attached to a cross-linked polystyrene.
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PMID:Artificial metalloprotease with active site comprising aldehyde group and Cu(II)cyclen complex. 1598 87

This paper describes the preparation, characterization, and enzymatic activity of complex coacervate core micelles (C3Ms) composed of poly(acrylic acid) (PAA) and poly(N-methyl-2-vinyl pyridinium iodide)-b-poly(ethylene oxide) (PQ2VP-PEO) to which the antibacterial enzyme lysozyme is end-attached. C3Ms were prepared by polyelectrolyte complex formation between PAA and mixtures containing different ratios of aldehyde and hydroxyl end-functionalized PQ2VP-PEO. This resulted in the formation of C3Ms containing 0-40% (w/w) of the aldehyde end-functionalized PQ2VP-PEO block copolymer (PQ2VP-PEO-CHO). Chemical conjugation of lysozyme was achieved via reductive amination of the aldehyde groups, which are exposed at the surface of the C3M, with the amine groups present in the side chains of the lysine residues of the protein. Dynamic and static light scattering indicated that the conjugation of lysozyme to C3Ms prepared using 10 and 20% (w/w) PQ2VP-PEO-CHO resulted in the formation of unimicellar particles. Multimicellar aggregates, in contrast, were obtained when lysozyme was conjugated to C3Ms prepared using 30 or 40% (w/w) PQ2VP-PEO-CHO. The enzymatic activity of the unimicellar lysozyme-C3M conjugates toward the hydrolysis of the bacterial substrate Micrococcus lysodeikticus was comparable to that of free lysozyme. For the multimicellar particles, in contrast, significantly reduced enzymatic rates of hydrolysis, altered circular dichroism, and red-shifted tryptophan fluorescence spectra were measured. These results are attributed to the occlusion of lysozyme in the interior of the multimicellar conjugates.
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PMID:Complex coacervate core micelles with a lysozyme-modified corona. 1758 20

Amyloid aggregation of polypeptides is related to a growing number of pathologic states known as amyloid disorders. There is a great deal of interest in developing small molecule inhibitors of the amyloidogenic processes. In the present article, the inhibitory effects of some indole derivatives on amyloid fibrillation of hen egg white lysozyme (HEWL) are reported. Acidic pH and high temperatures were used to drive HEWL towards amyloid formation. A variety of techniques, ranging from thioflavin T fluorescence and Congo red absorbance assays to far-UV CD and transmission electron microscopy, were employed to characterize the HEWL fibrillation process. Among the indole derivatives tested, indole 3-acetic acid, indole 3-carbinol and tryptophol had the most inhibitory effects on amyloid formation, indole and indole 3-propionic acid gave some inhibition, and indole aldehyde and tryptophan showed no significant inhibition. Although indoles did not protect the HEWL native state from conformational changes, they were effective in diminishing HEWL amyloid fibril formation, delaying both the nucleation and elongation phases. Disaggregation of previously formed HEWL amyloid fibrils was also enhanced by indole 3-acetic acid. Various medium conditions, such as the presence of different anions and alcoholic cosolvents, were explored to gain an insight into possible mechanisms. These observations, taken together, suggest that the indole ring is likely to play the main role in inhibition and that the side chain hydroxyl group may contribute positively, in contrast to the side chain carbonyl and intervening methylene groups.
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PMID:Inhibition of amyloid fibrillation of lysozyme by indole derivatives--possible mechanism of action. 1802 26

Polymer-protein conjugation was performed using N-hydroxysuccinimide and aldehyde-terminated zwitterionic polymers, and the resulting polymer-protein conjugates were characterized by gel electrophoresis and fast protein liquid chromatography. Methacryloyloxyethyl phosphorylcholine (MPC) polymers were prepared by atom transfer radical polymerization in which the requisite functional end-groups for protein conjugation were embedded within the polymerization initiators. These phosphorylcholine polymers were conjugated to lysozyme as a model protein, as well as two therapeutic proteins, granulocyte colony stimulating factor (G-CSF) and erythropoietin (EPO). These MPC polymer-protein conjugates represent alternatives to PEGylated proteins, with the potential to provide improved efficacy in a therapeutic treatment relative to the protein itself.
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PMID:End-functionalized phosphorylcholine methacrylates and their use in protein conjugation. 1881 97

It is known that protein attachment to surfaces depends sensitively upon the local structure and environment of the binding sites at the nanometer scale. Using nanografting and reversal nanografting, both atomic force microscopy (AFM)-based lithography techniques, protein binding sites with well-defined local environments are designed and engineered with nanometer precision. Three proteins, goat antibiotin immunoglobulin G (IgG), lysozyme, and rabbit immunoglobulin G, are immobilized onto these engineered surfaces. Strong dependence on the dimension and spatial distribution of protein binding sites are revealed in antibody recognition, covalent attachment via primary amine residues and surface-bound aldehyde groups. This investigation indicates that AFM-based nanolithography enables the production of protein nanostructures, and more importantly, protein-surface interactions at a molecular level can be regulated by changing the binding domains and their local environment at nanometer scale.
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PMID:A nanoengineering approach for investigation and regulation of protein immobilization. 1920 5

The effect of PEGylation on cation exchange chromatography was studied with poly(ethylene glycol) of different chain lengths (5kDa, 10kDa and 30kDa) using lysozyme as a model system. A stable binding via reduction of a Schiff base was formed during random PEGylation on lysine residues with methoxy-PEG-aldehyde. A purification method for PEGylated proteins using cation exchange chromatography was developed, and different isoforms of mono-PEGylated lysozyme were isolated. TSKgel SP-5PW and Toyopearl GigaCap S-650M showed the best performance of all tested cation exchange resins, and the separation of PEGylated lysozyme could be also scaled up to semi-preparative level. Size-exclusion chromatography, SDS-PAGE and MALDI-TOF mass spectrometry were used for analysis. Separated mono-PEGylated lysozyme of different sizes was used to determine dynamic binding capacities (DBC) and selectivity of cation exchange chromatography resins. An optimization of binding conditions resulted in a more than 20-fold increase of DBC for Toyopearl GigaCap S-650M with 30kDa mono-PEGylated lysozyme.
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PMID:Analytical and preparative separation of PEGylated lysozyme for the characterization of chromatography media. 1996 19


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