Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.25.1 (proteasome)
 28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The equilibrium and kinetics of chlorophenol (CP) sorption by chitosan, poly D-glucosamine, were studied under simulated groundwater conditions. Lower temperature, from 25 degrees C to 15 degrees C and then 5 degrees C, markedly decreased the adsorption rates by a factor of 30-53% and 7-22%. Comparison between two types of chitosan, flakes and highly swollen beads, demonstrated that the maximum pentachlorophenol (PCP) uptake capacities in Langmuir and Freundlich models depend on the specific surface area of the particle. Low temperature (5 degrees C) significantly increased the PCP uptake capacity in comparison to higher temperatures (15 degrees C and 25 degrees C). PCP uptake capacity was halved at pH levels higher than 6.5, and NaCl concentrations greater than 1% blocked PCP sorption almost completely. Of five kinds of chlorophenols, i.e. 2,4,6-trichlorophenol (2,4,6-TCP), 3,4-dichlorophenol (3,4-DCP), 2,3-dichlorophenol (2,3-DCP), 2,6-dichlorophenol (2,6-DCP), 3-monochlorophenol (3-MCP), TCP had the maximum sorption efficiency on flake-type chitosan, followed by DCPs, and finally MCP (the three kinds of DCP, with the same elemental compositions, achieved similar sorption performances).
Water Res 2004 May
PMID:Removal of chlorophenols from groundwater by chitosan sorption. 1560 85

The proteasome is known to be the main enzymatic complex responsible for the intracellular degradation of altered proteins, and the age-related accumulation of modified lens proteins is associated to the formation of cataracts. The aim of this study was to determine whether the human lens proteasome becomes functionally impaired with age. The soluble and insoluble protein fractions of human lenses corresponding to various age-groups were characterized in terms of their levels of glyco-oxidative damage and found to show increasing anti-carboxymethyl-lysine immunoreactivity with age. Concomitantly, decreasing proteasome contents and peptidase activities were observed in the water-soluble fraction. The fact that peptidylglutamyl-peptide hydrolase activity is most severely affected with age suggests that specific changes are undergone by the proteasome itself. In particular, increasing levels of carboxymethylation were observed with age in the proteasome. It was concluded that the lower levels of soluble active enzymatic complex present in elderly lenses and the post-translational modifications affecting the proteasome may at least partly explain the decrease in proteasome activity and the concomitant accumulation of carboxymethylated and ubiquitinated proteins which occur with age.
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PMID:Age-dependent protein modifications and declining proteasome activity in the human lens. 1519 94

In 1995, we discovered new antiherpetic antibiotics, called fattiviracins. The producing organism was classified as a strain belonging to Streptomyces microflavus. The strain produced at least 13 fattiviracin derivatives (FV-1 to FV-13). Fattiviracins were obtained as a white amorphous powder, and their molecular weights are in the range of 1400 to 1500. They are readily soluble in water, methanol, pyridine, and DMSO, but insoluble in other organic solvents. Fattiviracins have macrocyclic diesters formed by the binding of two trihydroxy fatty acids and two D-glucose residues in the molecule, and they can be divided into five families according to the length of the fatty acid moiety. Fattiviracins have potent activity against enveloped DNA viruses such as the herpes family, HSV-1, and VZV and enveloped RNA viruses such as influenza A and B viruses, and three strains of HIV-1, with EC(50) values on the order of a few micrograms per milliliter. The biosynthetic pathway of fattiviracins is also becoming clearer. Using bacitracin-resistant strains, enhanced and astringent production of fattiviracin was achieved. Fattiviracin FV-13, which has the longest fatty acid chains in the molecule, was dramatically enhanced by a C(55)-isoprenyl phosphate metabolism. In addition, we have screened various inhibitors of enzymes such as alkaline protease, glucosyltransferase, glucuronidase, phospholipase, deoxyribonuclease, DNA methyltransferase, and DNA topoisomerase. All the inhibitors we discovered are briefly summarized in this paper.
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PMID:[Metabolites produced by actinomycetes--antiviral antibiotics and enzyme inhibitors]. 1529 17

Cachexia is a syndrome and therefore does not have a specific definition. Patients are characterized by the presence of anorexia, early satiety, weight loss, weakness, anaemia and oedema. These features occur to a variable extent in different patients and may change in severity during the course of a patient's illness. The multifactorial origin of cachexia precludes a uniform pathophysiological definition. Taken together these factors have hindered clinical studies both at a fundamental level and in terms of the introduction of effective therapy. The advent of novel therapeutic targets (e.g., ubiquitin-proteasome pathway) and biological response modifiers has opened possibilities for new clinical trials in cachexia. Regulatory authorities feel it is important not only to demonstrate efficacy in terms of patients' nutritional status (e.g., lean body mass) but also functional status (e.g., performance status). This article reviews current methods to assess the latter. Methods focused on measuring physical activity level (e.g., doubly labelled water technique or physical activity meters) promise objective data which can be readily interpreted in terms of clinically meaningful benefit.
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PMID:Research methodology: cancer cachexia syndrome. 1533 19

This paper describes highly selective transesterification reactions, catalyzed by an alkaline protease from Bacillus subtilis in pyridine, of several mono- and di-saccharides with divinyl dicarboxylates ranging from 4 to 10 carbon atoms. A series of polymerizable vinyl fatty acid sugar esters were obtained with good selectivity and high yields. Most products had high proportions of the alpha anomer. The influences of the enzymes, solvents, temperature, and acyl donor chain length on the reaction were studied. Vinyl sugar esters offer a new family of functional water-soluble monomers for preparation of sugar-containing polymers.
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PMID:Regiospecific alkaline protease-catalyzed divinyl acyl transesterifications of primary hydroxyl groups of mono- and di-saccharides in pyridine. 1535 89

Enzymatic transesterification of guanosine having low solubility against organic solvent was examined. For the transesterification between guanosine and divinyl adipate catalyzed by alkaline protease from Bacillus (Bioprase), DMSO was added to DMF to increase the solublility of the nucleoside, and the conversion rate of guanosine to the vinyl guanosine ester was less than 30%. To overcome the reversible inactivation of enzyme by hydrophilic organic solvents, the reaction was carried out with 10% (v/v) water. The transesterification reaction was effectively catalyzed in DMF/DMSO in the presence of water and the conversion rate increased ca. 70% after 7 d reaction. The result shows that the water effect of Bioprase would be a useful method for the synthesis of low solublility nucleoside esters.
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PMID:Enzymatic transesterification of purine nucleoside having a low solubility in organic medium. 1548 83

Watermelon (Citrullus lanatus Thunb. Mansfeld) fruit were held in 50 microL/L of ethylene at 20 degrees C following 18 h application with 5 microL/L of 1-methylcyclopropene (1-MCP) to investigate the involvement of ethylene in the regulation of water-soaking. The early responses of watermelon fruit to ethylene were increased electrolyte leakage and free juice content, accompanying softening and water-soaking of placental tissue. Early evidence of water-soaking appeared in the inner pericarp near the calyx end after 2 d of ethylene treatment, and was accompanied by increased activities of ACC synthase (ACS) and ACC oxidase (ACO). While the application of 1-MCP showed no significant effects by itself, it completely suppressed water-soaking induced by exogenous ethylene. Water-soaking also developed in fruit stored over 10 d in air, and the affected fruit exhibited climacteric respiration and ethylene production peaks after 2 d of storage. These results, along with the observed prophylactic effects of 1-MCP, suggest that water-soaking in watermelon fruit is an ethylene-induced senescence phenomenon.
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PMID:Induction of water-soaking deterioration in watermelon fruit by ethylene. 1559 24

Arsenic present in drinking water and mining environments in some areas has been associated with an increased rate of skin and internal cancers. Contrary to the epidemiological evidence in humans, arsenic does not induce cancer in animal models, but is able to enhance the mutagenicity of other agents. In order to achieve a better understanding of the interaction between arsenic and ionising radiation, an investigation was conducted to detect differences at the proteome level of human TK6 lymphoblastoid cells exposed to these agents. Cells were exposed to either a single dose of 1-Gy 137Cs-gamma-rays or to 1 microM arsenite (As(III)) or to both agents in combination. Two-dimensional (2D) electrophoresis and matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) were employed for the screening and identification of proteins, respectively. It proved possible to identify seven proteins with significantly affected abundance, three of which showed increased levels and the remaining four showed decreased levels under at least one of the exposure conditions. Following arsenite treatment or irradiation, a significant increase compared with that of the control was observed for glutathione (GSH) transferase omega 1 and proteasome subunit beta type 4 precursor. The combined exposure did not result in an induction of the enzymes. The expression of electron-transfer flavoprotein subunit alpha was found to be enhanced under all three-exposure conditions. Ubiquinol-cytochrome C reductase complex core protein I, adenine phosphoribosyl transferase and endoplasmic reticulum protein hERp29 showed decreased levels after irradiation or arsenite treatment, but not after the combined exposure. The level of serine/threonine protein phosphatase 1 alpha decreased with all treatments. The main conclusions are that both arsenite and gamma-radiation influence the levels of several proteins involved in major metabolic and regulatory pathways, either directly or by triggering the defence mechanisms of the cell. The combined effect of both exposures on the level of some essential proteins such as glutathione transferase, proteasome or serine/threonine phosphatase may contribute to the co-carcinogenic effect of arsenic.
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PMID:Combined effects of gamma radiation and arsenite on the proteome of human TK6 lymphoblastoid cells. 1572 13

Meta-cleavage product hydrolase (MCP-hydrolase) is one of the key enzymes in the microbial degradation of aromatic compounds. MCP-hydrolase produces 2-hydroxypenta-2,4-dienoate and various organic acids, according to the C6 substituent of the substrate. Comprehensive analysis of the substrate specificity of the MCP-hydrolase from Pseudomonas fluorescens IP01 (CumD) was carried out by determining the kinetic parameters for nine substrates and crystal structures complexed with eight cleavage products. CumD preferred substrates with long non-branched C6 substituents, but did not effectively hydrolyze a substrate with a phenyl group. Superimposition of the complex structures indicated that benzoate was bound in a significantly different direction than other aliphatic cleavage products. The directions of the bound organic acids appeared to be related with the k(cat) values of the corresponding substrates. The Ile139 and Trp143 residues on helix alpha4 appeared to cause steric hindrance with the aromatic ring of the substrate, which hampers base-catalyzed attack by water.
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PMID:A series of crystal structures of a meta-cleavage product hydrolase from Pseudomonas fluorescens IP01 (CumD) complexed with various cleavage products. 1578 76

Three beta-cyclodextrin (beta-CD) conjugates of non-steroidal anti-inflammatory drugs were synthesized by enzymatic methods. Transesterification of beta-CD with vinyl ester of indomethacin, ketoprofen and etodolac was performed by the catalysis of alkaline protease from Bacillus subtilis in anhydrous DMF for 3 days. The drug molecules were selectively conjugated onto one of the secondary hydroxyl groups of beta-CD through ester-linkage to improve their poor water solubility and absorption characteristics. The products were characterized by ESI-MS, (1)H NMR and (13)C NMR. The structures of products with monoacylation occurring at the C-2 secondary hydroxyl groups of beta-CD were confirmed.
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PMID:Regioselective synthesis of cyclodextrin mono-substituted conjugates of non-steroidal anti-inflammatory drugs at C-2 secondary hydroxyl by protease in non-aqueous media. 1586 95


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