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)

Using ultracentrifugation, the systems of reversed micelles of aerosol OT in octane containing solubilized protein (alpha-chymotrypsin, lysozyme, trypsin, egg albumin, alcohol dehydrogenase from horse liver and gamma-globulin) were studied. The changes in the sedimentation coefficients of reversed micelles during incorporation of the protein are correlated (within a wide range of experimental conditions, e. g. degree of surfactant hydration or protein concentration) exclusively with the molecular weight of the solubilized protein. The simplest solubilization model, according to which the protein molecule is incorporated into the inner cavity of the reversed micelle at the stoichiometric ratio of 1 : 1, which does not affect the external sizes of the reversed micelle, has been proposed. Using alpha-chymotrypsin as an example, the conditions, under which the sedimentation properties of the systems deviate from this model, have been found. These deviations occurred at sufficiently low degrees of the surfactant hydration, when the inner cavity of the reversed micelle is smaller than the effective size of the solubilized protein molecule. In the latter case the protein forms a new micelle of necessary (i. e. larger) size. Since the hydrated micelle can be regarded as an elementary (30-100 A) fragment of biomembranes, the results obtained should be taken into consideration when analyzing the structural organization and functioning of the latter.
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PMID:[Enzymes incorporated into reversed micelles of surfactants in organic solvents. Study of the protein-aerosol OT-H2O-octane system by sedimentation analysis]. 617 48

1. The synthesis described is of p-azidophenylglyoxal (p-APG) by diazotization of p-aminoacetophenone to an intermediate which when reacted with sodium azide gives p-azidoacetophenone; oxidation of the latter with selenium dioxide gives rise to p-APG (corrected melting point, 103-105 degrees C). The phenylglyoxal moiety was designed to react with arginine residues, whereas the p-azidoaryl function generates a reactive nitrene when activated with UV light; p-APG reacts most selectively with arginine and to a lesser extent with cystine and histidine. 2. p-APG has absorption peaks at 205 and 280 nm which decrease on photolysis. 3. Bovine heart lactic dehydrogenase, egg white lysozyme, horse liver alcohol dehydrogenase, and yeast alcohol dehydrogenase, all enzymes having arginyl residues at their active sites, are inhibited by p-APG in the dark. 4. Gel electrophoresis of oligomeric enzymes having arginyl residues at their active sites and exposed to p-APG and to UV irradiation gave varying proportions of monomers and photocross-linked dimers, trimers, tetramers, and larger molecular weight aggregates.
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PMID:p-Azidophenylglyoxal. A heterobifunctional photoactivable cross-linking reagent selective for arginyl residues. 702 66

Fumarase (EC 4.2.1.2) and mitochondrial L-malate dehydrogenase (EC 1.1.1.37) were both inhibited by NaAuCl4 and KAuBr4. The inhibition for both was measured as a function of gold complex concentration and aquation time, and the NaAuCl4 inhibition was also measured in the presence of 0.15 M NaCl. Regeneration of the enzyme activity after NaAuCl4 inhibition using L-cysteine, L-methionine and NaCN was also investigated. Sodium dodecyl sulfate (SDS) acrylamide gel electrophoresis and amino acid analysis was performed on the NaAuCl4 inhibited enzymes as well as on ribonuclease A (EC 3.1.26.2), lysozyme (EC 3.2.1.17) and liver alcohol dehydrogenase (EC 1.1.1.1). It was observed that the inhibition was proportional to the gold complex concentration but decreased markedly after aquation of the complex. In the presence of NaCl the initial rate of inactivation is essentially unaffected unless the complex has been aquated and then the initial rate is increased. Gel electrophoresis on gold complex-enzyme mixtures show polymerization for ribonuclease and lysozyme and amino acid analysis indicates that no oxidation has taken place. From these results, a binding mechanism is postulated for the inhibition of the dehydrogenases by direct displacement of a halide ligand, probably by two groups on the enzyme, at least one of which may be a sulfur containing acid.
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PMID:Inhibition of two mitochondrial enzymes by gold (III) halo complexes. Evidence for a binding mechanism. 715 Dec 34

Pyocyanin being added to protein solutions influenced the intensity of the subsequent chemiluminescence caused by KMnO4. The amplitude of chemiluminescence for albumin, peptone and peroxidase decreased by 38, 39 and 42%, respectively. Pyocyanin had only a minor effect on the chemiluminescence of alcohol dehydrogenase; it decreased the intensity of the reaction by 7%. The reaction of chemiluminescence for cytochrome c and lysozyme did not change in the presence of pyocyanin.
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PMID:[Effect of pyocyanin on the intensity of KMnO4-induced protein chemiluminescence]. 744 75

Refolding of denatured-reduced lysozyme and the effect of co-refolding it with other proteins such as RNase A, bovine serum albumin, histone, myelin basic protein, alcohol dehydrogenase and DNase I on the renaturation yield and the aggregation of lysozyme have been studied. Basic proteins consistently increase the renaturation yield of the basic protein lysozyme (10-20% more than in their absence) with little or no aggregation. On the other hand, co-refolding of lysozyme with acidic proteins leads to aggregation and a significant decrease in renaturation yields. Our results show that hetero-interchain interactions (non-specific interactions) occur when the basic protein lysozyme is refolded together with acidic proteins such as bovine serum albumin, alcohol dehydrogenase or DNase I. Our results also suggest that the net charge on proteins plays a significant role in such non-specific aggregation. These results should prove useful in understanding the hetero-interchain interactions between folding polypeptide chains.
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PMID:Co-refolding denatured-reduced hen egg white lysozyme with acidic and basic proteins. 942 46

A new analytical approach has been applied to the determination and characterization of mercury-accessible -SH groups in pure native protein samples (ovalbumin, hemoglobin, glyceraldehyde-3-phosphate dehydrogenase, aldolase, pyruvate kinase, hexokinase, lactate dehydrogenase, alcohol dehydrogenase, creatine phosphokinase, lysozyme, and cytochrome c). The method is based on the selective reduction of Hg(II) in the presence of Hg(II)-thiol complexes with alkaline sodium tetrahydroborate, to give Hg(0) in a continuous flow reaction system coupled with atomic fluorescence spectrometric (AFS) detection. The method is fast and specific and allows one to work with nanomole amounts of a single protein without any preliminary incubation and without any separation of Hg(II) from thiol-complexed mercury. The meaning of the results obtained in the determination of the accessible -SH groups in native proteins by using chemical probes is discussed.
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PMID:Application of mercury cold vapor atomic fluorescence spectrometry to the characterization of mercury-accessible -SH groups in native proteins. 1052 12

Effects of the water activity (a(w)) and the solvent ordering, as determined by the activity coefficient of water, were investigated on the enzyme kinetics of alcohol dehydrogenase, lysozyme, and beta-galactosidase in various aqueous solutions. The water activity and the solvent ordering were adjusted by addition of electrolytes (NaCl, KCl, CsCl, etc.) or nonelectrolytes (sugars, alcohols, urea, etc.) at various concentrations. Although the enzyme kinetics were strongly dependent on a(w), a(w) was not a complete determinant of the enzyme behavior in aqueous solutions. Enzyme kinetics were also dependent on the solvent ordering. At a fixed a(w), all the enzyme kinetic parameters tested had a good correlation with the solvent ordering parameter as represented by the parameter alpha, an index of the deviation of the water state from the ideal solution, determined from the activity coefficient of water in solutions. Solvent ordering was expected to affect the enzyme kinetics through its effect on the hydrophobic interaction between the enzyme and the substrate and also on the thermal fluctuation.
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PMID:Influence of water activity and aqueous solvent ordering on enzyme kinetics of alcohol dehydrogenase, lysozyme, and beta-galactosidase. 1071 6

A novel magnetic support was prepared by an oxidization-precipitation method with poly(vinyl alcohol) (PVA) as the entrapment material. Transmission electron microscopy indicated that the magnetic particles had a core-shell structure, containing many nanometer-sized magnetic cores stabilized by the cross-linked PVA. The particles showed a high magnetic responsiveness in magnetic field, and no aggregation of the particles was observed after the particles had been treated in the magnetic field. These facts indicated that the particles were superparamagnetic. Cibacron blue 3GA (CB) was coupled to the particles to prepare a magnetic affinity support (MAS) for protein adsorption. Lysozyme was used as a model protein to test the adsorption properties of the MAS. The adsorption equilibrium of lysozyme to the MAS was described by the Langmuir-type isotherm. The capacity for lysozyme adsorption was more than 70 mg/g MAS (wet weight) at a relatively low CB coupling density (3-5 micromol/g). In addition, 1.0 M NaCl solution could be used to dissociate the adsorbed lysozyme. Finally, the MAS was recycled for the purification of alcohol dehydrogenase (ADH) from clarified yeast homogenates. Under proper conditions, the magnetic separation yielded over 5-fold purification of the enzyme with 60% recovery of the enzyme activity.
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PMID:A novel magnetic affinity support for protein adsorption and purification. 1117 Apr 91

Aggregation of alpha-synuclein is thought to play a major role in the pathogenesis of Parkinson's disease (PD), which is characterized by the presence of intracytoplasmic Lewy bodies (LB) in the brain. alpha-Synuclein and its deletion mutants are largely unfolded proteins with random coil structures as revealed by CD spectra, fluorescence spectra, gel filtration chromatography, and ultracentrifugation. On the basis of its highly unfolded and flexible conformation, we have investigated the chaperone-like activity of alpha-synuclein in vitro. In our experiments, alpha-synuclein inhibited the aggregation of model substrates and protected the catalytic activity of alcohol dehydrogenase and rhodanese during heat stress. In addition, alpha-synuclein inhibited the initial aggregation of reduced/denatured lysozyme on the refolding pathway. Interestingly, deletion of the C-terminal regions led to the abolishment of chaperone activity, although largely unstructured conformations are maintained. Moreover, alpha-synuclein could inhibit the aggregation of various Escherichia coli cellular proteins during heat stress, and C-terminal deletion mutants could not provide any protection to these cellular proteins. Results with synthetic C-terminal peptides and C-terminal deletion mutants suggest that the second acidic repeat, (125)YEMPSEEGYQDYEPEA(140), is important for the chaperone activity of alpha-synuclein, and C-terminal deletion leads to the facilitated aggregation with the elimination of chaperone activity.
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PMID:Structural and functional implications of C-terminal regions of alpha-synuclein. 1242 41

BACKGROUND: Use of lactose-rich concentrates from dairy processes for the induction of recombinant gene's expression has not received much attention although they are interesting low cost substrates for production of recombinant enzymes. Applicability of dairy waste for induction of recombinant genes in Escherichia coli was studied. Clones expressing Lactobacillus phage muramidase and Lactobacillus alcohol dehydrogenase were used for the experiments. RESULTS: Shake flask cultivations in mineral salt medium showed that cheese whey or deproteinised whey induced gene expression as efficiently as IPTG (isopropyl-beta-D-thiogalactopyranoside) or pure lactose. Addition of yeast extract or proteolytically degraded whey proteins did not improve the recombinant protein yield. In contrast, addition of yeast extract to the well-balanced mineral salt medium decreased the product yield. Feeding with glycerol provided sufficient amount of easily assimilable carbon source during the induction period without preventing lactose intake and induction by lactose. High-cell-density fed-batch cultivations showed that product yields comparable to IPTG-induction can be achieved by feeding bacteria with a mixture of glycerol and concentrated whey permeate during the induction. CONCLUSION: Whey and concentrated whey permeate can be applied as an alternative inducer in recombinant high-cell-density fed-batch fermentations. The yield of the recombinant product was comparable to fermentations induced by IPTG. In low-cell-density shake flask experiments the yield was higher with whey or whey permeate than with IPTG.
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PMID:Cheese whey-induced high-cell-density production of recombinant proteins in Escherichia coli. 1274 45


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