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)

Normal adult dogs were given intravenously lysine hydrochloride to abolish renal tubular reabsorption. The treatment caused tubular proteinuria. Once forced diuresis was established, fractional clearances for amylase, lipase, and lysozyme increased five-, 18-, and 857-fold over the baseline values, respectively. There was relatively little tubular reabsorption of amylase, and urinary amylase activity remained low. A renal arteriovenous difference in amylase activity was not present. Urinary amylase activity could not be reactivated by the addition of serum or treatment with dithiothreitol. Urinary inhibitors of amylase activity were not detected. Immunoreactive urinary amylase did not exceed kinetically measured urinary amylase. Therefore, the presence of irreversibly inactivated amylase did not explain the low fractional clearance of amylase. A small amount of serum macroamylase was present, but macroamylasemia did not account for canine amylase failing to pass the glomerular filter. It appears that the renal loss of amylase in the dog is not an important excretory route.
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PMID:Renal disposition of amylase, lipase, and lysozyme in the dog. 246 6

The influence of a soluble anionic polymer on electrophoresis of proteins was studied in relation to the nonspecific ionic effect of an affinophore on application to affinophoresis. Zone electrophoresis of proteins was carried out in agarose gel in the presence of succinyl-poly-L-lysine (degree of polymerization, 120) by using three electrophoresis buffers differing in ionic strength (0.06, 0.12 and 0.18) and pH (7.0 and 7.9). Proteins migrated as distinct single bands even in the presence of the polymer. The mobility of cationic proteins towards the cathode was first decreased and then increased towards the anode as the polymer concentration increased, while that of anionic proteins was not affected. The dependence of the apparent mobility changes of the proteins on the concentration of the polymer was treated quantitatively in the same way as affinity electrophoresis. The extent of the ionic interaction between a cationic protein and the polymer could be estimated as an apparent dissociation constant. It greatly depended on the ionic strength of the electrophoresis buffer. Except for the extremely cationic proteins such as lysozyme, the ionic interaction with up to 0.1 mM of the polymer could be practically suppressed by the use of 0.1 M sodium phosphate buffer (pH 7.0).
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PMID:Influence of a soluble anionic polymer on the electrophoresis of proteins. 247 57

Arginine 115 in the subsite F of human lysozyme (peptidoglycan N-acetylmuramoylhydrolase, EC 3.2.1.17) was replaced with lysine, histidine, glutamine or glutamine acid by site-directed mutagenesis. The conversions which conserve positive charge, Arg115 to Lys or His (at acidic pH), have little affected on either the kinetic parameters for Micrococcus lysodeikticus cells or the activity against glycol chitin, nor on the cleavage patterns of hexa(N-acetylglucosamine) [(GlcNAc)6] and penta(N-acetylglucosamine) [(GlcNAc)5]. On the other hand, the conversions which cause loss of the positive charge, Arg115 to His (neutral and alkaline pH), Gln or Glu, not only reduced the activity against glycol chitin but also changed the cleavage patterns for (GlcNAc)6 and (GlcNAc)5. These results suggest that Arg115 is structurally required not for the specific hydrogen bonding interaction with a sugar residue but for the positively charged character in the construction of subsite F in human lysozyme.
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PMID:A structural requirement in the subsite F of lysozyme. The role of arginine 115 in human lysozyme revealed by site-directed mutagenesis. 249 74

Soluble reduced lysozyme was extensively digested by a trypsin-like protease purified from the culture supernatant of the bacterium. The digestion peptides were separated and purified by reversed-phase high-performance liquid chromatography, and were subjected to amino acid analysis. The fragments were identified by their amino acid composition, and the cleavage sites in the lysozyme chain were determined. Like mammalian trypsin, the enzyme from B. gingivalis split peptide bonds non-specifically at carboxyl sides of internal arginine and lysine residues, but the lysine present at the amino terminus of the lysozyme chain was not released. In addition, the enzyme cleaved the peptide linkage at the amino side of lysine and bonds between leucine-glycine, alanine-leucine and leucine-serine. Thus the trypsin-like protease from B. gingivalis has some cleavage actions on lysozyme different from those of mammalian trypsin.
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PMID:Cleavage action of a trypsin-like protease from Bacteroides gingivalis 381 on reduced egg-white lysozyme. 251 80

The stabilization of the folded conformation of lysozyme, arising from the binding of the inhibitor (NAG)3 against induced denaturation, is demonstrated from the 1H-nmr spectra of the enzyme. The nmr spectra reveal that the binding of the denaturant (GuHCl) to the enzyme is associated with changes in the conformation of the enzyme. The binding site of the inhibitor site C also serves as one of the binding sites of GuHCl. The observation that higher denaturant concentrations are required in the unfolding of Lys-(NAG)3 as compared to free Lys can be explained partly in terms of the existence of a competitive binding to the enzyme involving the (NAG)3 and GuHCl molecules.
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PMID:NMR studies on the induced denaturation of lysozyme by guanidine hydrochloride in the presence of the inhibitor (NAG)3. 259 39

Previous studies have shown that chronic murine allergic arthritis can only be induced with cationized BSA, related to excellent retention of the cationic antigen in the joint. We now investigate the impact of size of cationic proteins on their potential to induce this form of arthritis. After intra-articular injection, antigen retention is much enhanced with high molecular weight cationized proteins, like albumin or immunoglobulin, compared to small-sized proteins like myoglobulin and lysozyme. Consequently, severe chronic arthritis was only found with the former ones. The role of size is further substantiated with poly-L-lysine-coupled lysozyme. This derivative shows excellent retention in vivo and causes a chronic destructive arthritis in preimmunized mice, in contrast to the poor arthritis seen with native cationic lysozyme. Control experiments made it clear that antigen retention is the most important denominator and that differences in chronicity are not related to gross variations in T-cell reactivity. Retention studies in vitro revealed that the potential to bind to joint structures is similar for the various proteins, suggesting that in vivo conditions determine size-related differences in antigen clearance. Our data indicate that cationicity per se does not make a protein a proper arthritogen.
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PMID:Allergic arthritis induced by cationic proteins: role of molecular weight. 276 9

A novel two-step procedure has been developed to prepare cytochrome c derivatives labeled at specific lysine amino groups with ruthenium bis(bipyridine) dicarboxybipyridine [RuII(bpy)2(dcbpy)]. In the first step, cytochrome c was treated with the mono-N-hydroxysuccinimide ester of 4,4'-dicarboxy-2,2'-bipyridine (dcbpy) to convert positively charged lysine amino groups to negatively charged dcbpy-lysine groups. Singly labeled dcbpy-cytochrome c derivatives were then separated and purified by ion-exchange chromatography. In the second step, the individual dcbpy-cytochrome c derivatives were treated with RuII(bpy)2CO3 to form singly labeled RuII(bpy)2(dcbpy-cytochrome c) derivatives. The specific lysine labeled in each derivative was determined by reverse-phase chromatography of a tryptic digest. All of the derivatives had a strong luminescence emission centered at 662 nm, but the luminescence decay rates were increased relative to that of a non-heme protein control, RuII(bpy)2(dcbpy-lysozyme), which was 1.8 X 10(6) s-1. The luminescence decay rates were found to be 21, 16, 7.2, 5.7, 4.3, 4.3, and 3.5 X 10(6) s-1 for derivatives singly labeled at lysines 13, 72, 25, 7, 39, 86, and 87, respectively. There was an inverse relationship between the luminescence decay rates and the distances between the ruthenium labels and the heme group. The increased luminescence decay rates observed in the cytochrome c derivatives might be due to electron transfer from the excited triplet state of ruthenium to the ferric heme group. However, it is also possible that an energy-transfer mechanism might contribute to the luminescence quenching.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Preparation and characterization of singly labeled ruthenium polypyridine cytochrome c derivatives. 284 87

An extracellular, acidic chitinase was purified to homogeneity from tobacco necrosis virus-infected leaves of Cucumis sativis. The amino acid sequences of the intact protein and of peptides isolated following endoproteinase Lys-C digestion, cyanogen bromide cleavage, and trypsin digestion were determined. Oligonucleotide probes derived from this sequence were used to isolate a cDNA clone encoding this protein. No significant homology was found between this chitinase and either the basic chitinase isolated from bean or tobacco or the chitinase isolated from Serratia marcescens; however, strong homology was found between the cucumber chitinase and a lysozyme/chitinase from Parthenocissus quinquifolia. The induction of the protein by tobacco necrosis virus infection or salicylate was found to be at the level of RNA accumulation. Genomic Southern analysis indicates that a single gene in the cucumber genome encodes this protein.
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PMID:Isolation of a complementary DNA encoding a chitinase with structural homology to a bifunctional lysozyme/chitinase. 291 85

Circular dichroism studies on synthetic peptides corresponding to the signal sequences of chicken lysozyme and Escherichia coli proteins, lambda-receptor and lipoprotein, have been carried out in trifluoroethanol. The peptides, (CH3)3-C-O-CO-Thr-Leu-Lys-Lys-Leu-Pro-Leu-Ala-Val-Ala-Val-Ala-Ala-Gly- Val-Met-Thr-Ala- Ala-Met-Ala-OCH3, (CH3)3-C-O-CO-Met-Lys-Ser-Leu-Leu-Ile-Leu-Val-Leu-Cys(benzyl)- Phe-Leu-Pro- Leu-Ala-Ala-Leu-Gly-OH and (CH3)3-C-O-CO-Leu-Val-Leu-Gly-Ala-Val-Ile-Leu-Gly- Thr-Thr-Leu-Leu- Ala-Gly-OCH3, corresponding to the signal sequences of lambda-receptor, lysozyme and the hydrophobic region of lipoprotein, respectively, show two negative bands at approx. 205 and 220 nm, characteristic of an alpha-helical conformation. Secondary structural features are discernible even in the shorter, 12-residue carboxy-terminal fragments of these signal peptides. A comparison of the conformation of the amino-terminal, central and carboxy-terminal fragments of lipoprotein signal sequence indicates that the central octapeptide fragment is more structurally ordered compared to the amino- and carboxy-terminal fragments.
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PMID:Circular dichroism studies on synthetic signal peptides. 293 58

Egg white lysozyme, treated with O-methylisourea to convert lysine to homoarginine residues, was used as a substrate for the ATP-dependent proteolytic pathway in rabbit reticulocyte lysates. Although guanidinated lysozyme was degraded by an ATP-dependent, hemin-sensitive process, ubiquitin conjugates of this protein were present at less than 5% the level of conjugates between ubiquitin and nonguanidinated lysozyme. When lysates were chromatographed on DEAE-cellulose to produce Fractions I and II of (Hershko et al. (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 3107), ubiquitin-depleted Fraction II was capable of degrading nonguanidinated lysozyme, but the degradation of guanidinated lysozyme was markedly reduced or abolished. Glycerol-stabilized Fraction II, on the other hand, supported the degradation of both proteins in an ATP-dependent process stimulated by ubiquitin. The degradation of the two proteins differed, however, in that guanidinated lysozyme was more sensitive to competitive substrates, and higher concentrations of ubiquitin were required for its maximal proteolysis. Despite ubiquitin stimulation of guanidinated lysozyme degradation, only trace amounts of higher molecular weight species of guanidinated lysozyme attributable to ubiquitin conjugation were observed in ubiquitin-supplemented, glycerol-stabilized Fraction II even when special precautions were employed to preserve labile covalent bonds. These results indicate that covalent attachment of ubiquitin to the epsilon-amino group of substrate lysines is not mandatory for ATP-dependent proteolysis in rabbit reticulocyte lysates. The observation that ubiquitin stimulates proteolysis of guanidinated lysozyme, without extensive conjugation to it, suggests that ubiquitin may have essential functions for proteolysis other than direct marking of the protein substrate.
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PMID:The degradation of guanidinated lysozyme in reticulocyte lysate. 300 5


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