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)

A method for determination of amino acid composition of proteins separated by SDS-polyacrylamide gel electrophoresis and transferred to polyvinylidene difluoride (PVDF) membranes is described. A single blotted band containing 50 to 200 pmoles of protein was cut out and submitted to acid hydrolysis with HCl followed by derivatization with phenylisothiocyanate. The amino acid derivatives were separated by reverse phase high-performance liquid chromatography. Bovine serum albumin, lysozyme, myoglobin, ovalbumin, soybean trypsin inhibitor and carbonic anhydrase were analyzed; the results revealed a good correspondence with reported values. This can be considered an analytical method to determine the amino acid composition of samples from microquantities of protein mixtures, particularly in those cases in which SDS-polyacrylamide gel electrophoresis is the most suitable separation system.
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PMID:Micro-determination of amino acid composition of proteins electroblotted onto polyvinylidene difluoride membranes. 263 61

The interaction of tryptophan, lysozyme and tyrosine with ninhydrin in strong acid media has been investigated at 20, 25, 30, and 35 degrees C by spectrophotometry. Second-order rate constants and molar absorptivity values have been evaluated from an analytical point of view. Optimum conditions for the selective estimation of tryptophan, tryptophan residues in intact proteins, and indoles--without the disturbing effect of tyrosine--have been given. Under optimum conditions, in the concentration range from 2.5 X 10(-8) to 3.0 X 10(-7)M, molar absorptivity values and reproducibility data for various reactants have been reported. Molar absorptivity values (Am X 10(-3)/M X cm) of tryptophan (21.35), lysozyme (19.33), bovine serum albumin (21.05), human serum albumin (21.00), casein (17.85), alpha-chymotrypsin (18.28), trypsin (14.43), indole (5.03), and indole-3-acetic acid (13.75) have been measured with a standard error of 2.3% or less for any particular reactant.
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PMID:Spectrophotometric determination of tryptophan in intact proteins by the acid ninhydrin method. 274 46

The ultrafiltration properties of isolated glomerular basement membrane were studied in vitro by forming membrane fragments into thin films for use as ultrafiltration membranes. The filtration properties of the films were examined using cytochrome c, myoglobin, lysozyme, ovalbumin, lactoglobulin, and serum albumin. The films behaved as compressible filters showing size-dependent rejection of the proteins. The behavior of the films was modelled using the fiber matrix hypothesis which gave good prediction of film behavior. The membrane behaved as a random fiber matrix composed of fibers of 0.8-1.0 nm in radius.
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PMID:Glomerular basement membrane as a compressible ultrafilter. 276 32

In these investigations Cibacron Blue F3GA was immobilized on soft gels, porous silicas, and non-porous glass beads. Hen egg white lysozyme, human serum albumin and yeast alcohol dehydrogenase were used as adsorbates with the dye-affinity sorbents. Batch experiments with continuous monitoring of protein concentration were employed to evaluate thermodynamic and kinetic behaviour of these proteins in finite bath systems. The observed adsorption kinetic rates of interaction of the above proteins with each of the dye-affinity sorbents were found to decrease with increasing protein molecular weight. Equilibration times, in the batch experimental mode, of the adsorption of lysozyme on the dye-affinity sorbents varied from 20 s for the non-porous glass beads with a size range of 20-40 microns to more than 60 min in the case of a porous sorbent with a particle diameter of 100-300 microns and 60 nm pore size. Furthermore, equilibration times, which represent the overall adsorption rates incorporating all the non-equilibrium effects, increased with all affinity systems when adsorption took place in the non-linear portion of the isotherm. The most dramatic increase was observed when sorbents with relatively high protein size to pore size ratios, lambda, were employed.
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PMID:High-performance liquid chromatography of amino acids, peptides and proteins. XCII Thermodynamic and kinetic investigations on rigid and soft affinity gels with varying particle and pore sizes. 277 75

S-mercuric-N-dansylcysteine was investigated as a potential probe of protein sulphydryl groups using bovine serum albumin, S-carboxymethyl-bovine serum albumin, lysozyme, and partially reduced lysozyme as test proteins. Criteria used to assess covalent binding through mercury-bridged mercaptide linkages include a finite reaction time (minutes to hours), abolition of the characteristic fluorescence spectrum following addition of a reducing agent, and failure to separate probe and protein after chromatography or electrophoresis. By these criteria, both Torpedo californica acetylcholinesterase and human serum cholinesterase (butyrylcholinesterase) contain four free sulphydryl groups per tetrameric enzyme molecule whereas Electrophorus electricus acetylcholinesterase has none. Labeled acetylcholinesterase and butyrylcholinesterase remain active and responsive to the inactivator Zn2+. Zn2+ promotes an increase in the fluorescence of bound S-mercuric-N-dansylcysteine, whereas activators such as Mg2+ or gallamine promote a decrease, suggesting that the label may be a useful probe of ligand-induced conformational changes. With T. californica acetylcholinesterase, but not with human serum cholinesterase, Zn2+ also promotes access to two additional groups that are reactive towards the sulphydryl reagent.
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PMID:The reaction of S-mercuric-N-dansylcysteine with acetylcholinesterase and butyrylcholinesterase. 278 87

The effect of calcitriol on the induction of differentiation in human promyelocytic leukemic cell line (HL-60) cultured in serum-free chemically defined medium (SFM) was investigated. The utilization of SFM containing RPMI-1640 basal medium supplemented with insulin (5 micrograms/ml), transferrin (5 micrograms/ml), sodium selenite (5 ng/ml), and bovine serum albumin (0.5 micrograms/ml), transferrin examination of the cellular/molecular mechanism of calcitriol's action in HL-60 cell differentiation without interference of components present in serum. HL-60 cells grown in SFM were induced to differentiate into monocytes/macrophages by calcitriol as indicated by induction of differentiation-associated biological and biochemical parameters: chemiluminescent (CL) responsiveness, lysozyme activity, nonspecific esterase, expression of cell surface antigens, and reduced proliferation. The exposure of HL-60 cells in SFM to calcitriol (from 10(-10) to 10(-8)M) resulted in dose-dependent induction of these parameters, which was similar to those obtained with cells grown in 10% fetal calf serum containing medium (10% SCM). However, calcitriol was 5-fold more potent for HL-60 cells cultured in SFM than those cultured in 10% SCM as indicated by shifts in dose-response curves for induction of CL responsiveness and lysozyme activity. The effect of calcitriol on the proliferation and acquisition of several monocyte-associated cell surface antigens was also more sensitive for HL-60 cells cultured in SFM than for cells grown in 10% SCM. We characterized and quantitated calcitriol receptors in HL-60 cells cultured in SFM in comparison to those in 10% SCM after exposing intact cells to radiolabeled calcitriol. Cells cultured in either SFM or 10% SCM exhibited calcitriol receptors that migrated at 3.4S as a single peak on sucrose gradients and elicited inherent DNA binding ability. There was essentially no difference in the apparent dissociation constants (Kd) nor in the number of calcitriol binding sites per HL-60 cell, that is approximately 6.0 X 10(-11) M and approximately 3000 binding sites/cell respectively. It is concluded that culturing HL-60 cells in SFM results in full expression of calcitriol-induced phenotypic changes excluding the possibility that such changes result from the indirect effect of calcitriol mediated by identified and/or unidentified components present in serum.
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PMID:Induction of monocytic differentiation by calcitriol (1,25-dihydroxyvitamin D3) in the human promyelocytic leukemic cell line (HL-60) in serum-free medium. 282 7

A post-translational protein modification system involving the polypeptide ubiquitin results in ubiquitin-protein conjugates of various functions. A ubiquitin-conjugating enzyme system was isolated from the epithelial tissue of bovine eye lens by DEAE-Sepharose and Bio-Gel A-1.5m column chromatography. The lens system shows similar enzymatic properties to the one from rabbit reticulocytes: requirement for ATP and sensitivity to thiol reagents. Two sets of prominent ubiquitin conjugates were formed with endogenous ubiquitin-acceptor proteins from fractions of the Bio-Gel column: a pair of ubiquitin conjugates of approximately 130 kDa and others with very high molecular mass. Extreme specificity is indicated by the ability of the lens system to catalyze conjugation of ubiquitin to the few endogenous acceptor proteins, or to histone H2B, but not to lysozyme, S-carboxymethylated bovine serum albumin, or native or heat-denatured lens alpha crystallin.
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PMID:Properties of the ubiquitin conjugation system from bovine eye lens. 284 35

Binding of the cationic molecule lysozyme to the glomerular basement membrane and to the glomerular epithelial cell coat was investigated in the glomerulus of normal female Wistar rats and in rats in which heavy proteinuria was induced by the daily administration of 1 g of bovine serum albumin. In normal rats the binding of lysozyme to the anionic groups in the glomerular basement membrane and the cell coat had no effect on the ultrastructure of the glomerular epithelial cell, in particular the foot processes were unchanged. In the proteinuric rats the lysozyme-binding to the glomerular basement membrane and the epithelial cell coat was completely lost in the damaged glomeruli. In the apparently normal glomeruli present in these proteinuric animals binding was similar to that seen in normal rats. These results suggest that in protein-overload proteinuria there is a loss of glomerular anion and hence a reduction in the glomerular charge barrier. This may account, at least in part, for the increased glomerular leak of negatively charged serum albumin in this experimental model of proteinuria.
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PMID:Glomerular lysozyme binding in protein-overload proteinuria. 286 90

Microcapsules (5-100 microns) were prepared through interfacial cross-linking of various proteins (human serum albumin, lysozyme, haemoglobin, casein, pepsin) with glutaraldehyde or terephthaloylchloride. Surprisingly they all showed an inhibitory effect on cultured cells in a concentration range of 100 micrograms ml-1 to 10 mg ml-1. This effect seemed non-specific, reversible and to depend on contact with the cell plasma membrane. The electric charges of microcapsules could be involved in the inhibition phenomenon.
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PMID:In-vitro cytotoxic activity of cross-linked protein microcapsules. 286 38

An acepromazine (ACP) hapten was synthesised, coupled to bovine serum albumin and injected into a horse to produce antibodies to the drug. A competitive ELISA was developed whereby ACP attached to the solid phase via lysozyme competed with free ACP present in phosphate buffered saline, horse serum or horse urine for limiting amounts of antibody. The assay could detect the presence of ACP and, or, some of its metabolites in horse urine for at least 25 hours after intravenous injection of 0.1 mg kg-1 ACP maleate, but because of non-specific interference, horse serum could not be used. As little as 0.24 micrograms ml-1 ACP or its metabolites could be detected. The level of detection and the ease of performance of the assay make it an attractive alternative to the more complex methods currently available for the screening of horse urine samples at horse races, shows and sales.
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PMID:Development of an enzyme-linked immunosorbent assay for the detection of phenothiazine tranquillisers in horses. 288 18


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