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)

Polycationic polymers have been noted for their effects in promoting cell adhesion to various surfaces, but previous studies have failed to describe a mechanism dealing with this type of adhesion. In the present study, three polycationic polymers (chitosan, poly-L-lysine, and lysozyme) were tested for their effects on microbial hydrophobicity, as determined by adhesion to hydrocarbon and polystyrene. Test strains (Escherichia coli, Candida albicans, and a nonhydrophobic mutant, MR-481, derived from Acinetobacter calcoaceticus RAG-1) were vortexed with hexadecane in the presence of the various polycations, and the extent of adhesion was measured turbidimetrically. Adhesion of all three test strains rose from near zero values to over 90% in the presence of low concentrations of chitosan (125 to 250 micrograms/ml). Adhesion occurred by adsorption of chitosan directly to the cell surface, since E. coli cells preincubated in the presence of the polymer were highly adherent, whereas hexadecane droplets pretreated with chitosan were subsequently unable to bind untreated cells. Inorganic cations (Na+, Mg2+) inhibited the chitosan-mediated adhesion of E. coli to hexadecane, presumably by interfering with the electrostatic interactions responsible for adsorption of the polymer to the bacterial surface. Chitosan similarly promoted E. coli adhesion to polystyrene at concentrations slightly higher than those which mediated adhesion to hexadecane. Poly-L-lysine also promoted microbial adhesion to hexadecane, although at concentrations somewhat higher than those observed for chitosan. In order to study the effect of the cationic protein lysozyme, adhesion was studied at 0 degree C (to prevent enzymatic activity), using n-octane as the test hydrocarbon. Adhesion of E. coli increased by 70% in the presence of 80 micrograms of lysozyme per ml. When the negatively charged carboxylate residues on the E. coli cell surface were substituted for positively charged ammonium groups, the resulting cells became highly hydrophobic, even in the absence of polycations. The observed "hydrophobicity" of the microbial cells in the presence of polycations is thus probably due to a loss of surface electronegativity. The data suggest that enhancement of hydrophobicity by polycationic polymers is a general phenomenon.
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PMID:Mechanism of enhancement of microbial cell hydrophobicity by cationic polymers. 221 2

A chitinase purified from culture filtrates of Trichoderma resei KDR-11 efficiently catalyzed a transglycosylation reaction on tetra-N-acetylchitotetraoside in a buffer medium containing ammonium sulfate, converting the tetrasaccharide into hexa-N-acetylchitohexaose (39.6%) and di-N-acetylchitobiose (55.7%) as the major products. Sugar-chain elongation from di-N-acetylchitobiose as the initial substrate to hexa-N-acetyl-chitohexaose and hepta-N-acetylchitoheptaose was also efficiently induced through lysozyme catalysis in the presence of ammonium sulfate at high (30%) concentration. In this case, the addition of ammonium sulfate to the reaction system resulted in a remarkable increase of the hexamer and heptamer productions, which are desirable as biologically active oligosaccharides.
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PMID:Enzymic synthesis of useful chito-oligosaccharides utilizing transglycosylation by chitinolytic enzymes in a buffer containing ammonium sulfate. 222 4

The lysozyme from the fungus of the Chalaropsis species has been crystallized. This lysozyme (Mr 22,415) displays no sequence homology with avian, phage, or mammalian lysozymes, however, preliminary studies indicate significant sequence homology with the bacterial lysozyme from Streptomyces. Both enzymes are unusual in possessing beta-1,4-N-acetylmuramidase and beta-1,4-N,6-O-diacetylmuramidase activity. The crystals grow from solutions of ammonium sulfate during growth periods from several months to a year. The space group is P2(1)2(1)2(1) with a = 34.0 A, b = 42.6 A, c = 122.1 A. Preliminary data indicate that there is 1 molecule/asymmetric unit. A complete native data set has been collected to 2.57-A resolution. The crystals are highly ordered and exhibit diffraction patterns to d-spacings less than 1.5 A.
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PMID:Preliminary crystallographic examination of a novel fungal lysozyme from Chalaropsis. 232 6

A comparison of the efficiencies of hydrophobic interaction chromatography, ion-exchange chromatography, reversed-phase chromatography and gel permeation chromatography in the separation of tear proteins was made using a variety of different buffers. Separation of immunoglobulins, lactoferrin, albumin, PMFA (protein migrating faster than albumin) and lysozyme was accomplished by gel permeation chromatography in less than 30 min using a TSK-type SW3000 column equilibrated with ammonium acetate buffer (pH 4.1) with a high reproducibility. When gel permeation chromatography was used as a completely automated diagnostic method, only minute volumes (1.0 microliter) of tear samples were necessary for the quantitative analysis of proteins. The other three methods proved to be more suitable for the preparation of individual tear proteins but were less suitable for their quantitation.
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PMID:Analysis of human tear proteins by different high-performance liquid chromatographic techniques. 232 62

Shaken cultures of Streptomyces venezuelae ISP5230 in minimal medium with galactose and ammonium sulphate as carbon and nitrogen sources, respectively, showed extensive sporulation after 72 h incubation at 37 degrees C. The spores formed in these cultures resembled aerial spores in their characteristics. The ability of the spores to withstand lysozyme treatment was used to monitor the progress of sporulation in cultures and to determine the physiological requirements for sporulation. In media containing ammonium sulphate as the nitrogen source, galactose was the best of six carbon sources tested. With galactose S. venezuelae ISP5230 sporulated when supplied with any of several nitrogen sources; however, an excess of nitrogen source was inhibitory. In cultures containing galactose and ammonium sulphate, sporulation was suppressed by a peptone supplement. The onset of sporulation was accompanied by a drop in intracellular GTP content. When decoyinine, an inhibitor of GMP synthase, was added to a medium containing starch and ammonium sulphate, a slight increase in sporulation was seen after 2 d. The suppression of sporulation by peptone in liquid or agar cultures was not reversed by addition of decoyinine. A hypersporulating mutant of S. venezuelae ISP5230 was altered in its ability to assimilate sugars. In cultures containing glucose the mutant sporulated more profusely than did the wild-type and did not acidify the medium to the same extent. However, the suppressive effect of glucose on sporulation was not merely a secondary result of acid accumulation.
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PMID:Sporulation of Streptomyces venezuelae in submerged cultures. 239 93

A system for the rapid isolation of low molecular weight proteins from urine has been devised, and illustrated by alpha 1-microglobulin, beta 2-microglobulin, retinol binding protein, lysozyme and monoclonal light chains. Urine proteins from patients with tubular dysfunction were concentrated, either by ultrafiltration or ammonium sulphate precipitation. This was followed by gel chromatography on Sephadex G-50. The appropriate fractions were then separated by chromatography on Pharmacia monobead columns. A Mono Q strong anion exchanger was used for beta 2-microglobulin, retinol binding protein, alpha 1-microglobulin and free monoclonal light chains. Lysozyme was separated on a Mono S cation exchanger. The chromatography was first optimized on HR 5/5 columns and then scaled up to HR 16/10 columns.
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PMID:Fast protein liquid chromatography scale-up procedures for the preparation of low-molecular-weight proteins from urine. 241 49

Adjuvants differ in capacity to induce interferon (IFN). As a consequence IFN induction by adjuvants may influence their effectiveness in enhancement of delayed type hypersensitivity (DH) reactions. In this study, the lipophilic amine dimethyl dioctadecyl ammonium bromide (DDA), the synthetic double-stranded polynucleotide polyinosinic polycytidylic acid (poly I:C), liposomes and the polyols L 101 and L 121 were compared in BALB/c mice as inducers of IFN and also as adjuvants for DH to both lysozyme and inactivated Semliki Forest virus (SFV). The antigens were injected intracutaneously, alone or mixed with adjuvant. At day 6 after the immunization, DH was elicited and measured 24 h later as increase in footpad thickness. Negatively charged liposomes and polyol L 121 were unable to enhance DH to SFV and also lack the capacity to induce IFN. Polyol L 101 induced low levels of IFN and showed only slight adjuvanticity for DH to SFV. In contrast, DDA, a moderate IFN inducer, was shown to be a very effective adjuvant for induction of DH against both lysozyme and SFV. The excellent IFN inducer, poly I:C, at the tested dose range (0.03-3.0 mg/kg), displayed only a relatively weak adjuvant activity. But low doses of poly I:C (0.03 and 0.1 mg/kg) showed still adjuvanticity in contrast to equal doses of DDA. This might be related to sufficient induction of IFN by low doses of poly I:C but not by DDA. The discrepancy observed in the relation between IFN induction and a maximal DH induction suggests that IFN is not the only factor which enhances the effectiveness of adjuvants in induction of DH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Potentiation of the cellular immune response by adjuvants: a limited role for adjuvant induced interferon. 242 55

The catalytic activities of lysozyme, horseradish peroxidase (HP), catalase, glucose-6-phosphate dehydrogenase (G6PDH) and lactate dehydrogenase (LDH) were studied in aqueous solutions and after isolation of the enzymes from mixed reversed micelles of Aerosol OT and Triton X-45 by organic solvents (acetone, ethanol, isopropanol), by acetone-water mixtures, as well as by aqueous solutions containing urea, glycerol, polyethylene glycol 6000 and ammonium sulphate. The isolation conditions were found for catalase with retaining all the activity and for HP and lysozyme with retaining 72 and 84% of the catalytic activity, respectively. The G6PDH isolation from micelles by aqueous solutions of urea (6%) and glycerol (10%) resulted in retaining only 43% of the enzyme activity and led to almost complete inactivation of LDH. Stability of the enzymes after their entrapment in micelles and isolation from those is compared with thermostability of the same enzymes in aqueous solutions.
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PMID:[Isolation of enzymes from mixed reversed micelles of surface-active agents]. 245 51

Allophycocyanin (APC) belongs to a family of phycobiliproteins that are well suited as fluorescent reagents for flow cytometric analysis, since they have a broad excitation spectrum, a large Stoke's shift and they fluoresce with a high quantum yield. The widespread use of APC has been limited by the availability of raw material and high cost of the purified phycobiliprotein. We have assessed the suitability of dry, powdered Spirulina platensis, available at health food stores, as an inexpensive source of APC. APC was extracted from Spirulina platensis by overnight treatment with lysozyme, followed by ammonium sulfate precipitation. APC was then separated from phycocyanin (the only other major phycobiliprotein in Spirulina) by elution of bound material from an hydroxylapatite column using an increasing continuous phosphate gradient. APC isolated in this manner retained its normal trimeric structure. The absorbance and fluorescence excitation and emission spectra of the purified phycobiliproteins were identical to those previously shown for C-PC and APC. APC can be stored concentrated at 4 degrees C, frozen at -70 degrees C, or as a saturated ammonium sulfate precipitate, with no subunit dissociation or change in spectral properties. Moreover, APC has been conjugated to monoclonal and polyclonal antibodies for use in multicolor FACS analysis, with the conjugated antibody activity remaining stable for at least 2 years. Thus, this procedure is a simple, cost-effective method for preparing reagents for multicolor immunofluorescence and flow cytometry.
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PMID:A novel and inexpensive source of allophycocyanin for multicolor flow cytometry. 250 78

The steady-state twist of Bacillus subtilis macrofibers produced by growth in complex medium was found to vary as a function of the magnesium and ammonium concentrations. Four categories of macrofiber-producing strains that differed in their response to temperature regulation of twist were studied. Macrofibers were cultured in the complex medium TB used in previous experiments and in two derivative media, T (consisting of Bacto Tryptose), in which most strains produced left-handed structures, and Be (consisting of Bacto Beef Extract), in which right-handed macrofibers arose. In nearly all cases, increasing concentrations of magnesium led to the production of macrofibers with greater right-handed twist. Some strains unable to form right-handed structures as a function of temperature could be made to do so by the addition of magnesium. Inversion from right- to left-handedness in strain FJ7 induced by temperature shift-up was blocked by the addition of magnesium. The presence of magnesium during a high-temperature pulse did not block the establishment of "memory," although it delayed the initiation of the transient inversion following return to low temperature. The twist state of macrofibers grown without a magnesium supplement was not instantaneously affected by the addition of magnesium. Such fibers were, however, protected from lysozyme attack and associated relaxation motions. Lysozyme degradation of purified cell walls (both intact and lacking teichoic acid) was also blocked by the addition of magnesium. Ammonium ions influenced macrofiber twist development towards the left-hand end of the twist spectrum. Macrofiber twist produced in mixtures of magnesium and ammonium was strain and medium dependent.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of Bacillus subtilis macrofiber twist development by ions: effects of magnesium and ammonium. 310 May 2


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