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)

Peptides containing Lys-Pro-Arg or Thr-Lys-Arg segments corresponding to various regions of human C-reactive protein were synthesized. The peptides prepared were composed of amino acid residues, 37-58, 51-58, 173-187 and 181-187 of C-reactive protein. The relationship between C-reactive protein, its synthetic fragments and tuftsin (Thr-Lys-Pro-Arg) was investigated in binding studies, enhancement of phagocytosis and change in cyclic nucleotide levels of mouse macrophages. The peptides AA 51-58 and 181-187 did enhance macrophage phagocytosis capacity to a similar extent to that of tuftsin. They showed however only negligible binding to the cells. The effect of C-reactive protein and the synthetic peptides on metabolic activity of neutrophils was also investigated. It was shown that the peptides inhibited to some degree superoxide production, lysozyme release and Vitamin B12 binding protein release from neutrophils in the absence and presence of the stimulants, PMA or Con A. Comparable activity with tuftsin was not found.
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PMID:Synthetic peptides from C-reactive protein containing tuftsin-related sequences. 303 32

Lysozyme was reacted with xylose, methyl linoleate, glyoxal, methylglyoxal and diacetyl in an aqueous system (50 degrees C, pH 6.0), and browning, polymerization, changes of amino acids composition and relative digestibility of the browned lysozyme were investigated. Browning intensity as well as degree of polymerization of lysozyme in the reaction with alpha-dicarbonyls was higher than with xylose or methyl linoleate. After 10 days of reaction with alpha-dicarbonyls, the amino acid composition of lysozyme was markedly affected; i.e., 30-70% of lysine, 40-50% of tryptophan and 90% of arginine were lost respectively. By digestion with a pepsin-pancreatin system, it was observed that the relative digestibility of lysozyme reacted with dicarbonyl was lower than that of lysozyme reacted with methyl linoleate or xylose.
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PMID:Changes of amino acids composition and relative digestibility of lysozyme in the reaction with alpha-dicarbonyl compounds in aqueous system. 308 26

Two lower-molecular-weight derivatives of recombinant human interferon-gamma (rIFN-gamma) were purified concurrently from a lysozyme-EDTA extract of Escherichia coli cells by immunoaffinity chromatography using a monoclonal antibody (MAb) against a synthetic carboxy-terminal peptide (Lys-131-Gln-146). The two derivatives, 15K rIFN-gamma and 17K rIFN-gamma, were regarded to have been generated at the extraction step. They were successfully separated from each other by using another MAb against the same synthetic peptide with higher binding affinity than the first. The results of protein-chemical analyses indicate that 15K rIFN-gamma and 17K rIFN-gamma lack 15 (Arg 132-Gln-146) and 4 (Arg-143-Gln-146) carboxy-terminal amino acid residues, respectively. All the data suggest that the two derivatives form a noncovalent dimer and that 15K rIFN-gamma binds indirectly to the MAb column via 17K rIFN-gamma.
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PMID:Differential purification by immunoaffinity chromatography of two carboxy-terminal portion-deleted derivatives of recombinant human interferon-gamma from Escherichia coli. 311 44

The characteristics of ADP-ribosyltransferase activity in skeletal muscle membranes have been studied. The membrane enzymes can ADP-ribosylate exogenous substrates such as guanylhydrazones, polyarginine, lysozyme, and histones. The properties of the enzyme are investigated by using diethylaminobenzylidineaminoguanidine as a model substrate. Incubation of the membranes with [32P]adenylate-labeled NAD results in the labeling of a number of cellular proteins. Magnesium ions, detergents, and diethylaminobenzylidineaminoguanidine stimulated the ADP-ribosylation of membrane proteins, whereas L-arginine methyl ester and arginine inhibited ADP-ribosylation. The labeling of specific proteins in the sarcoplasmic reticulum and glycogen pellet is influenced significantly by detergents, nucleotides, and thiols. The hydroxylamine sensitivity of the ADP-ribose linkage in the membrane proteins is similar to that reported for (ADP-ribose)-arginine linkage. Snake venom phosphodiesterase digestion of the ADP-ribosylated membranes produces 5'-AMP as the major acid-soluble digestion product. The results suggest that the primary mode of modification is mono(ADP-ribosyl)ation. The ADP-ribosyltransferase activity in the membrane preparations is not extracted under conditions used for solubilization of extrinsic proteins, suggesting that the activity is associated with some integral membrane protein.
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PMID:Endogenous ADP-ribosylation in skeletal muscle membranes. 312 54

Some human urine is bactericidal for the F-62 strain of Neisseria gonorrhoeae. Gonococci of three auxotypes (Pro-; Arg-, Hyx-, Ura-; and Pro-, Arg-. (Orn*), Ura-) were tested by in-vitro exposure to 31 samples of urine from 14 men. Nineteen of the urine specimens were bactericidal, and 12 were not. Except for one sample, all cidal urines came from five men. Cidal activity was associated with acidic, concentrated urines; it was unaffected by exposure to lowered pH, pronase, heat or cold, and was dialyzable with use of a dialysis membrane with a cut-off molecular weight of 1000. Neutralization of the acid urines removed the antigonococcal activity. Noncidal acid urines became cidal urines when concentrated by lyophilization. Zinc, lysozyme, fluoride ions, and fatty acids are substances that have antibacterial activity and are also present in urine. These substances were examined for antigonococcal activity. Neither zinc salts, fluoride ions, lysozyme, nor fatty acids in concentrations exceeding those found in urine were bactericidal for the gonococci. These results show that sufficiently concentrated, acidic urines kill gonococci by an unknown mechanism.
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PMID:Bactericidal properties of urine for Neisseria gonorrhoeae. 312 16

We have purified two high molecular weight proteases approximately 400-fold from rabbit reticulocyte lysate. Both enzymes hydrolyze 125I-alpha-casein and 4-methylcoumaryl-7-amide peptides with tyrosine, phenylalanine, or arginine at the P1 position. Both are inhibited by hemin, thiol reagents, chymostatin, and leupeptin. They differ, however, by other criteria. Degradation of 125I-lysozyme-ubiquitin conjugates and succinyl-Leu-Leu-Val-Tyr-4-methylcoumaryl-7-amide by the larger 26 S protease is stimulated by ATP. Based on sedimentation, gel filtration, and nondenaturing polyacrylamide gel electrophoresis, the ATP-dependent protease has a molecular weight of 1,000,000 +/- 100,000 and is a multisubunit complex. The smaller 20 S protease has a molecular weight of 700,000 +/- 20,000 and is composed of 8-10 separate subunits with Mr values between 21,000 and 32,000. It does not require nucleotides for degradation of protein or peptide substrates. This smaller enzyme is similar, if not identical, to the "multicatalytic proteinase complex" first described by Wilk and Orlowski (Wilk, S., and Orlowski, M. (1983) J. Neurochem. 40, 842-849).
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PMID:Purification of two high molecular weight proteases from rabbit reticulocyte lysate. 329 29

To elucidate the structure-function relationship of the signal sequence for the secretion of human lysozyme by Saccharomyces cerevisiae, we have systematically engineered the hydrophobic segment using the signal sequence of chicken lysozyme. Replacement of Cys 10 with leucine caused a 1.6 times increase in the secretion of human lysozyme. An idealized signal sequence L10 in which 10 consecutive leucines were distributed from the 3rd to the 12th position was 1.8 times as effective as the native sequence. L10 can be generalized as Ln = Met-Arg-(Leu)n-Pro-Leu-Ala-Ala-Leu-Gly, where n = 10. We have also studied the secretory capability of Ln, where n = 6,8,12, and 14, and found that the length, as well as hydrophobicity, of the hydrophobic segment is an important factor in the secretion of human lysozyme by yeast.
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PMID:Engineering of the hydrophobic segment of the signal sequence for efficient secretion of human lysozyme by Saccharomyces cerevisiae. 332 76

Previous studies have indicated that at least part of the selection of proteins for degradation takes place at a binding site on ubiquitin-protein ligase, to which the protein substrate is bound prior to ligation to ubiquitin. It was also shown that proteins with free NH2-terminal alpha-NH2 groups bind better to this site than proteins with blocked NH2 termini (Hershko, A., Heller, H., Eytan, E., and Reiss, Y. (1986) J. Biol. Chem. 261, 11992-11999). In the present study, we used simple derivatives of amino acids, such as methyl esters, hydroxamates, or dipeptides, to examine the question of whether the protein binding site of the ligase is able to distinguish between different NH2-terminal residues of proteins. Based on specific patterns of inhibition of the binding to ligase by these derivatives, three types of protein substrates could be distinguished. Type I substrates are proteins that have a basic NH2-terminal residue (such as ribonuclease and lysozyme); these are specifically inhibited by derivatives of the 3 basic amino acids (His, Arg, and Lys) with respect to degradation, ligation to ubiquitin, and binding to ligase. Type II substrates (such as beta-lactoglobulin or pepsinogen, that have a Leu residue at the NH2 terminus) are not affected by the above compounds, but are specifically inhibited by derivatives of bulky hydrophobic amino acids (Leu, Trp, Phe, and Tyr). In these cases, the amino acid derivatives apparently act as specific inhibitors of the binding of the NH2-terminal residue of proteins, as indicated by the following observations: (a) derivatives in which the alpha-NH2 group is blocked were inactive and (b) in dipeptides, the inhibitory amino acid residue had to be at the NH2-terminal position. An additional class (Type III) of substrates comprises proteins that have neither basic nor bulky hydrophobic NH2-terminal amino acid residues; the binding of these proteins is not inhibited by homologous amino acid derivatives that have NH2-terminal residues similar to that of the protein. It is concluded that Type I and Type II proteins bind to distinct and separate subsites of the ligase, specific for basic or bulky hydrophobic NH2-terminal residues, respectively. On the other hand, Type III proteins apparently predominantly interact with the ligase at regions of the protein molecule other than the NH2-terminal residue.
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PMID:Specificity of binding of NH2-terminal residue of proteins to ubiquitin-protein ligase. Use of amino acid derivatives to characterize specific binding sites. 334 27

A proton nuclear magnetic resonance (NMR) study is reported of the molecular structural basis of antigen-antibody interactions. An immunologically reactive proteolytic fragment corresponding to one of the antigenic regions on hen egg-white lysozyme (HEL) was used in combination with a monoclonal antibody that recognizes this site. Using spin diffusion, we prepared an antibody in which the magnetization of the antigen binding site was saturated by non-specific nuclear Overhauser effect. Under these conditions the effect of the saturation of the antibody was observed to spread over the peptide fragment through the antigen binding site. On the basis of the results obtained for the intermolecular nuclear Overhauser effect, we discuss how the peptide fragment interacts with the antibody. The side chains of aromatic residues, Trp, Tyr, and His, and of ionic residues, especially Arg, Lys, and Glu, are suggested to be important in the antigen-antibody interaction.
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PMID:A 1H NMR method for the analysis of antigen-antibody interactions: binding of a peptide fragment of lysozyme to anti-lysozyme monoclonal antibody. 342 50

The effects of two co-carcinogenic phorbol esters (phorbol myristate acetate (PMA) and phorbol dibutyrate (PDBu] and a synthetic diacylglycerol (OAG, 1-oleoyl-2-acetyl-glycerol), which all stimulate protein kinase C, were compared with two inactive phorbol compounds (4 alpha-phorbol and 4 alpha-phorbol didecanoate (4 alpha-PDD)) on three functional properties of stimulated human polymorphonuclear leukocytes (PMNs): release of granular enzymes lysozyme and beta-glucuronidase, chemokinesis, and changes in cytoplasmic free calcium [Ca2+]i. PMA, PDBu and the diacylglycerol, OAG, all caused a dose-dependent and slow (max by 15 min) release of small amounts of lysozyme with much less beta-glucuronidase and no release of cytoplasmic lactate dehydrogenase. Release was unaffected by removal of extracellular Ca2+. PMA, PDBu and OAG inhibited random movement of the cells, did not cause chemokinesis and induced a slow reduction in the basal [Ca2+]i, as measured by the quin-2 method. PMA, PDBu and OAG increased the capacity of five independently-acting stimulants (N-formyl-Met-Leu-Phe, leukotriene B4, C5a des-Arg, platelet activating factor and A23187) to cause release of lysozyme and beta-glucuronidase but strongly inhibited PMN chemokinesis induced by the same five agents and reduced the stimulant-induced increases in [Ca2+]i. PMA was always more potent than PDBu and much more potent than OAG in eliciting these stimulatory or inhibitory effects on human PMNs. In all tests, 4 alpha-phorbol and 4 alpha-PDD were inactive. The results confirm that stimulation of the diacylglycerol/protein kinase C system in human PMN, either by active phorbol esters or the synthetic diacylglycerol, causes bidirectional effects on human PMN function. In particular, activation of the C-kinase causes inhibition of stimulated neutrophil motility, whereas the secretory functions of the cells are enhanced.
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PMID:Divergent effects of co-carcinogenic phorbol esters and a synthetic diacylglycerol on human neutrophil chemokinesis and granular enzyme secretion. 347 47


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