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)

Various small fragments of (see article) which is one of the immunodominant groups of hen egg-white lysozyme (HL), were tested for macrophage migration inhibition (MMI) of peritoneal exudate cells (PEC) from guinea pigs immunized with HL. P17 was split in the middle with cyanogen bromide. The terminal portion of (see article) showed positive MMI, whereas the non-terminal half of P17, P17i (sequence 13-27) only showed very weak MMI activity. A fragment derived from the middle portion of P17, P17m (sequence 11-22), was inactive. When P17 were reduced and alkylated, one of the resultant peptides, P17N (sequence 1-[CM-Cys-6]-27) still has MMI activity with PEC taken from guinea pigs immunized with HL, although no antibody reacting with it was detected, but P17C (sequence 123-[CM-Cys-127]-129) was inactive. The peptides P17 and P17N were both immunogenic in guinea pigs in respect to the delayed hypersensitivity response. Again P17t and P17N were immunodominant groups, but the reactivity of P17i in MMI assay of this group of animals was greater than that in guinea pigs immunized with HL. The reactivities of HL with PEC taken from guinea pigs immunized with P17 or P17N were generally weaker than those of the antigens used for immunization.
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PMID:Antigenic determinants of hen egg-white lysozyme in delayed hypersensitivity. II. Antigenicity and immunogenicity of the N- and C-terminal peptide. 5 72

The continuous cell line, J774.2, exhibits many macrophage-like functions such as latex and Fc-mediated phagocytosis, antibody mediated phagocytosis, antibody mediated cytotoxicity, chemotaxis, and lysozyme secretion. Cyclic AMP stimulates Fc-mediated phagocytosis and inhibits the growth of J774.2. To further evaluate the relationship between cyclic AMP and the specialized functions exhibited by these cells. Variants deficient in phagocytosis, adenylate cyclase and cyclic AMP-dependent protein kinase were derived. We have now shown that J774.2 also secretes plasminogen activator and that this secretion is rapidly and specifically inhibited by 8-bromoadenosine 3':5'-cyclic monophosphoric acid (8 Br--cAMP) or cholera toxin under conditions where lysozyme secretion is unaltered. Utilizing protein kinase-deficient variants, the ability of cyclic AMP to inhibit plasminogen activator secretion was shown to be mediated by a cyclic AMP-dependent protein kinase. We conclude that cyclic AMP has diametrically opposing effects on two macrophage-like functions: Fc-mediated phagocytosis and plasminogen activator secretion.
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PMID:Inhibition of plasminogen activator secretion by cyclic AMP in a macrophage-like cell line. 21 71

Ion-exchange derivatives are described. of a hydrophilic rigid macroporous glycolmethacrylate gel called Spheron, suitable for rapid high-performance liquid chromatography (HPLC) of proteins and their fragments. Their flow parameters are compared with those of ion exchange derivatives of cellulose and polydextran. The conditions for work with them are described (regeneration, cycling, equilibration, column packing) as well as the construction of a simple apparatus for medium-pressure ion exchange chromatography of proteins. The efficiency of these ion exchangers for the separation of proteins is illustrated with examples of chromatography of an artificial mixture of serum albumin, chymotrypsinogen and lysozyme. Chromatography of cyanogen bromide fragments of serum albumin and the A and B chains of oxidized insulin showed that the method can be applied in chromatography on higher molecular protein fragments. A review of all proteins, including technical enzymes, which have already been chromatographed on Spheron ion exchangers is also given. The prospects of Spheron ion exchangers for HPLC of proteins and their fragments are briefly discussed.
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PMID:Rapid separation of proteins and their higher-molecular fragments by means of Spheron ion-exchanges. 39 17

During purification of E2R using oligo(dT)-cellulose chromatography, a receptor accessory factor (RAF) was identified in the cytosol of mouse kidney. This factor stimulates the binding of purified E2R to oligo(dT)-, oligo(dC)-, and oligo(dA)-cellulose as well as to DNA cellulose. It is a heat-stable, trypsin-resistant protein with an apparent molecular weight of between 10 and 30,000 daltons. Although structurally unrelated, similar stimulation of oligonucleotide binding was seen with calf thymus histones and, to a lesser extent, egg white lysozyme. Individual histones, especially H2a, H2B, and H3, also facilitate rebinding of purified E2R to oligo(dT)-cellulose, while H1 is less effective. Furthermore, histones stabilize the holoreceptor during sedimentation at 4 degrees and 12 degrees C. The N- and C-terminal half molecules of H2b were generated by cyanogen bromide-mediated cleavage and the N-terminal half was found to duplicate the effects of the parent molecule, both in binding and holoreceptor stabilization. These data suggest that the in vivo binding of E2R to DNA can be modulated by accessory proteins of cytosol and nuclear origin.
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PMID:Stimulation of oligonucleotide binding of estradiol receptor complexes by accessory proteins. 49 27

The binding isotherms of native bovine serum albumin with cationic detergents, such as octyl, decyl, dodecyl and tetradecylpyridinium bromides were determined at pH 6.8 and 3.4 at 25 degrees C. The isotherms for dodecyl and tetradecylpyridinium bromides were also determined at 3 degrees C. The average number of detergent cations bound increased with increasing hydrocarbon chain length. At low detergent concentration the binding of all alkylpyridinium bromides was smaller at pH 3.4 than at pH 6.8. Dodecylpyridinium bromide was bound to native beta-lactoglobulin, aldolase, ovalbumin, haemoglobin, myoglobin, lysozyme, trypsin and ribonuclease at pH 6.8. No binding occurred to alpha-chymotrypsin and chymotrypsinogen. The free enthalpy change, --delta G degrees, calculated from intrinsic association constants K was determined.
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PMID:Protein-cationic detergent interaction. Equilibrium dialysis study of the interaction of bovine serum albumin and other proteins with alkylpyridinium bromide. 49 43

Fourier transform infrared and laser Raman spectroscopies were used to study the effects of dodecylpyridinium bromide on the conformation of haemoglobin, myoglobin, bovine serum albumin, ribonuclease, ovalbumin, lysozyme, trypsin and beta-lactoglobulin in aqueous solution. Addition of the cationic detergent caused a decrease in alpha-helix conformation in highly helical proteins. At low detergent concentrations stabilization of beta-sheet conformation was observed.
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PMID:Protein-cationic detergent interaction. Fourier transform infrared and laser Raman spectroscopic studies on the interaction between proteins and dodecylpyridinium bromide. 49 44

Nuclear magnetic quadrupole relaxation appears to be a general method for studying the binding of anions to proteins. This is shown by the increase in transverse quadrupole relaxation rate of 35Cl- and 81Br- in the presence of horse liver alcohol dehydrogenase, lysozyme, trypsin, alpha-chymotrypsin, human carbonic anhydrase, fructose-1,6-bisphosphate aldolase and human serum albumin. Of the many possible binding sites at the surface of a protein (e.g. positively charged amino acid side-chains) only a few account for the main part of the relaxation enhancement. This is shown by the decrease in 35Cl- and 81Br- relaxation rate on addition of functional ligands. Large, kinetically inert, complex anions like Pt(CN)2-4 and Au(CN)-2 are found to act as strong competitors towards halogen ions for the high-affinity anion binding sites of a number of proteins. Titrations with complex anions following the 35Cl- or 81Br- relaxation rates are found to be helpful in attempts to elucidate binding mechanisms. Especially, the complex anions may be useful probes for the discrimination between general and metallic anion binding sites in proteins and they also permit correlation of information from X-ray investigations of crystals with that from physical measurements in solution. From the change in halide ion quadrupole relaxation rate on addition of strongly binding ligands the quadrupole coupling constants of the high affinity Cl- and Br- binding sites are estimated using certain assumptions. It is found that for several proteins, comprising the metal-free proteins but also alcohol dehydrogenase and Escherichia coli alkaline phosphatase, the 35Cl quadrupole coupling constants have approximately the same values. For some other metallo-proteins like carbonic anhydrase and a zinc - serum-albumin complex considerably greater quadrupole coupling constants were obtained. The estimated quadrupole coupling constants are used as a basis for a discussion of the interactions involved in anion-protein interactions.
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PMID:Pt(CN)2-4 and Au(CN)-2: potential general probes for anion-binding sites of proteins. 35Cl and 81Br nuclear-magnetic-resonance studies. 120 23

The relative susceptibilities of lenticular proteins (alpha, beta and gamma-crystallins) and a number of proteins of non-lenticular origin, to hydroxyl radical-mediated peptide bond cleavage were compared. The non-lenticular proteins (bovine serum albumin, ovalbumin, alcohol dehydrogenase, lysozyme, thyroglobulin, beta-amylase, haemoglobin and carbonic anhydrase) were readily cleaved into acid-soluble fragments following 5 hours treatment with copper ions and hydrogen peroxide. In contrast the crystallins were almost totally unaffected by similar treatment. When alpha-crystallin was pre-treated with acid or cleaved into large fragments with cyanogen bromide it became susceptible to hydroxyl radical attack, yet heating the protein did not diminish its resistance. It is suggested that the resistance of alpha-crystallin to the copper/peroxide-mediated fragmentation may be dependent on the conformation of the protein.
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PMID:Differences in susceptibility between crystallins and non-lenticular proteins to copper and H2O2-mediated peptide bond cleavage. 175 88

Previous studies have shown that reduced carbamoylmethylated lysozyme (RCAM-lysozyme, MW approximately 14.5K) is a substrate and inhibitor (Ki approximately 0.6 microM) of insulin receptor kinase (InsRK) autophosphorylation (Kohanski & Lane, 1986; Lane & Kohanski, 1986). In this study we have prepared a family of defined modified derivatives of RCAM-lysozyme and used them to probe the nature of the substrate and inhibitory sites of InsRK. All open-chain derivatives of lysozyme in which either the tryptophanyl, methionyl, cysteinyl, arginyl, or histidyl side chains were modified served as substrates and were potent inhibitors of InsRK autophosphorylation. This was true whether the substitutions were either hydrophilic or hydrophobic, although the hydrophilic derivatives had a higher inhibitory potency. Tryptic peptides derived from RCAM-lysozyme, however, were inactive as inhibitors, and a mixture of the three cyanogen bromide fragments (containing 12, 24, and 93 amino acids, respectively) was found to be less potent in inhibiting the receptor kinase. Derivatization of either tyrosyl or carboxyl side chains produced derivatives that were neither substrates nor capable of inhibiting receptor autophosphorylation. Derivatives with modified amino groups were substrates for InsRK but were not able to inhibit InsRK autophosphorylation. The present study suggests that (a) unphosphorylated InsRK has a large hydrophilic substrate binding domain and is effectively inhibited by long-chain polypeptides but not by short sequences, (b) some of the amino, carboxyl, and hydroxyphenyl side chains are essential to the inhibitory nature of these polypeptides, and (c) derivatives that fail to inhibit autophosphorylation can still be recognized and phosphorylated by active InsRK.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A family of polypeptide substrates and inhibitors of insulin receptor kinase. 216 Feb 65

A rapid procedure for the large-scale isolation of plasmid DNA is described. The method utilizes cetyltrimethylammonium bromide to precipitate the plasmid following extraction of DNA by lysozyme digestion and boiling. The plasmid is then purified by passing through the spin column pZ523. The purity and yield of the plasmid obtained with this method is similar to that isolated by cesium chloride-ethidium bromide gradient centrifugation. The method does not involve any phenol-chloroform extractions and takes five to six hours for completion after growth of the bacterial cells. The plasmid obtained is amenable to digestion with various restriction endonucleases, can be used for cloning with high efficiency and is also suitable as template for dideoxy sequencing.
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PMID:Large-scale isolation of plasmid DNA using cetyltrimethylammonium bromide. 216 86


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