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)

Endometrial explants were removed from uteri of animals pregnant and pseudopregnant (5 mg oestradiol valerate on Days 11--15) for 60 days, from the gravid and non-gravid horns of unilaterally pregnant pigs at Day 60 of pregnancy and fron non-pregnant animals at Day 12 of the oestrous cycle. The tissues were cultured in the presence of L-[34S]methionine for 24 h, and the tissues and medium were then analysed separately by two-dimensional polyacrylamide gel electrophoresis. Radioactive polypeptides were identified by autoradiography of dried gels. Tissues from all all except the cyclic animals released an identical group of polypeptides into the culture medium: the major radioactive products were 4 acidic polypeptides of low molecular weight and several basic proteins, which included the purple phosphatase uteroferrin, and lysozyme. In separate experiments explants from 3 unilaterally pregnant pigs were cultured with L-[3H]leucine, and, on a fresh weight basis, the tissue from the non-gravid horn released significantly less radioactive macromolecular material into the medium in 24 h than did tissue from gravid horns. It therefore appears that although the nature of the secretion produced by the pregnant uterus is a consequence of maternal hormonal regulation alone, the tissue underlying a conceptus is quantitatively more active than that from unoccupied regions of a uterus.
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PMID:Effect of the conceptus on quantitative and qualitative aspects of uterine secretion in pigs. 743 27

In order to determine if the rates of intracellular transport of oviduct secretory proteins are coordinate, oviduct minces were first incubated with either [3H]methionine or [3H]leucine. 2 h later, the minces were exposed to either [35S]methionine or [14C]leucine in addition to the 3H-labeled amino acid. After incubating for an additional 90-120 min, aliquots of the media were subjected to immunoprecipitation to isolate ovalbumin, conalbumin and lysozyme. From the 3H/35S or 3H/14C ratios in the isolated proteins, relative rates of intracellular transport were determined. The data obtained indicate that conalbumin and lysozyme exhibit similar rates of intracellular transport, whereas ovalbumin lags behind these proteins considerably. The basis for this effect is discussed in light of current knowledge concerning the synthesis and secretion of ovalbumin.
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PMID:Studies on the relative rates of intracellular transport of egg white proteins. 747 May 8

The synthesis and the biological activity towards human neutrophils of some N-formyl-Met-Leu-Phe-OMe analogues containing (S)-phenylalaninol (Pheol) or its derivatives in place of the native phenylalanine are reported. While the analogue containing Pheol (4) was found to be devoid of significant biological activity, its esters 3 and 5, although inactive as chemoattractants, are able to strongly stimulate superoxide production and are active with a lower efficacy in the lysozyme release.
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PMID:Chemotactic peptide analogues. Synthesis and chemotactic activity of N-formyl-Met-Leu-Phe analogues containing (S)-phenylalaninol derivatives. 748 25

A gamma-glutamyl peptide-hydrolysing enzyme was partially purified from Actinobacillus actinomycetemcomitans. The enzyme required metal ions, and 1 to 2 mM Mn2+ ions, especially, were essential for hydrolytic reaction. Its distribution by treatment of cells with lysozyme-EDTA suggested that the enzyme was a membrane-bound protein. The pI of the enzyme was in range of pH 5.1 to 5.6, and the apparent Km value for gamma-glutamyl-p-nitroanilide was 3.0 x 10(-4) M. The enzyme hydrolysed specifically gamma-glutamyl residues from the N-terminal of gamma-glutamyl compounds such as gamma-Glu-Met, gamma-Glu-Ala, gamma-Glu-Leu and gamma-Glu-Tyr, but did not catalyse the transpeptidation reaction. Neither free amino acids such as Ala-, Pro-, Gly- and Leu-p-nitroanilide nor alpha-glutamyl derivatives were hydrolysed. Its activity was strongly inactivated by metal chelators (EDTA or o-phenanthroline) and amino acids (Glu, Gln). In addition, the activity was specifically inactivated by gamma-glutamyl affinity-labelling reagents such as AT-125, 6-diazo-5-oxo-L-norleucine and azaserine, which are inhibitors of the gamma-glutamyl donor sites of mammalian gamma-glutamyl transpeptidase. Antibodies against bovine kidney gamma-glutamyl transpeptidase decreased the activity of the bacterial enzyme by 65%. These results suggested that the active sites in the bacterial enzyme were similar to those in mammalian gamma-glutamyl transpeptidase.
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PMID:Partial purification and some properties of gamma-glutamyl peptide-hydrolysing enzyme from Actinobacillus actinomycetemcomitans. 779 32

For-Met-delta ZLeu-delta ZPhe-OMe (3) has been synthesized as a new analogue of the prototypical chemotactic agent For-Met-Leu-Phe-OMe (fMLP-OMe). Compound 3 is characterized by presence of two consecutive alpha,beta-didehydro amino acid residues [delta ZLeu = (Z)-alpha,beta-didehydroleucine; delta ZPhe = (Z)-alpha,beta- didehydrophenylalanine] located at the central and C-terminal position, respectively. When tested on human neutrophils the N-formyltripeptide 3, although less active than the parent, is able to induce chemotaxis, superoxide anion production and lysozyme release. The activity of 3 has been compared to that of related fMLP-OMe analogues containing a single delta ZPhe residue located at the C-terminal position.
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PMID:Modified chemotactic peptides: synthesis and biological activity of HCO-Met-delta ZLeu-delta ZPhe-OMe. 783 75

The bacteriophage lambda R gene has been isolated into an Escherichia coli expression system and the R gene product, a lysozyme, has been overexpressed and purified to homogeneity using an efficient purification procedure. A turbidimetric assay utilizing chloroform-treated E. coli cells has been optimized to assess the bacteriolytic activity of the purified enzyme. Using this assay, oligomers of beta (1 --> 4) N-acetyl-D-glucosamine at high concentrations were shown to inhibit lysozyme but were not cleaved by the enzyme. Differential scanning calorimetry revealed that the thermal denaturation of lysozyme was found to increase in the presence of (GlcNAc)3 and (GlcNAc)5. The lysozyme was also expressed in an E. coli strain auxotrophic for methionine, allowing for the incorporation of [methyl-13C]methionine into the enzyme. An alteration of the [1H-13C]HMQC NMR spectra of the labelled enzyme was observed in the presence of (GlcNAc)5. Commercially available nitrophenyl glycosides did not act as substrates for lambda lysozyme. The results indicate that lambda lysozyme has specific interactions with oligosaccharides of N-acetylglucosamine, but is incapable of hydrolyzing these sugars. The relevance of the structure of peptidoglycan to the activity of lambda lysozyme is discussed.
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PMID:Investigations of the interactions of saccharides with the lysozyme from bacteriophage lambda. 787 85

This study investigated the intracellular distribution of lysozyme, a protein that is synthesized and secreted by rat alveolar type II epithelial (ATII) cells and alveolar macrophages, using a polyclonal antibody generated against purified rat lysozyme. Lysozyme was immunoprecipitated with this antibody from Triton X-100 lysates of ATII cells cultured on a basement membrane derived from Englebreth-Holme-Swarm mouse sarcoma (EHS) and radiolabeled with 35S-methionine. ATII cells cultured on EHS basement membrane for several days were fixed and labeled with antibodies to surfactant apoprotein A (SP-A) and lgp-120 (a lysosomal glycoprotein), or lysozyme and lgp-120, and studied by confocal microscopy. Organelles were identified that stained positively for either anti-lysozyme or anti-lgp-120; a second population of organelles contained both markers. Similarly, two populations of SP-A-containing organelles were identified; one contained the lysosomal glycoprotein lgp-120. In addition, confocal images demonstrated that both SP-A and lysozyme were secreted by ATII cells, as evidenced by the accumulation of secretory products within the lumen of the cyst-like aggregates. When the subcellular localization of SP-A and lysozyme was studied by analytical cell fractionation, two populations of organelles were identified that contained SP-A or lysozyme. The lighter population accounted for approximately 32% of SP-A and 33% of total intracellular lysozyme and was recovered in the same region of the gradient as secretory lamellar bodies. The more dense population co-localized with lysosomes and accounted for approximately 67% of both SP-A and lysozyme recovered. Western blots of cell fractions revealed intact lysozyme in all the cell fractions. The results of these experiments suggest that lysozyme has a similar intracellular distribution as surfactant apoprotein A in ATII cells. Lysozyme is found in fractions containing lamellar bodies where it is packaged for secretion, and in lysosomal fractions where it may undergo degradation.
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PMID:Intracellular distribution of lysozyme in rat alveolar type II epithelial cells. 788 8

For-Thp-Leu-delta ZPhe-OMe (2), an analogue of the chemotactic tripeptide For-Met-Leu-Phe-OMe, containing 4-aminotetrahydrothiopyran-4-carboxylic acid (Thp) and (Z)-2,3-didehydrophenylalanine (delta ZPhe) as achiral, conformationally restricted mimics of Met and Phe, respectively, has been synthesized. In the crystal the new formyltripeptide adopts a type I beta-turn conformation stabilized by a weak H bond between the formylic oxygen and the delta ZPhe NH. 1H-nmr analysis based on NH solvent accessibility and nuclear Overhauser effect experiments suggests that the beta-turn is not preferred in CDCl3 solution where a gamma-turn, centered at the Thp residue, prevails. The biological activity of 2 has been determined on human neutrophils and compared to that of previously studied analogues. The tripeptide 2 is practically unable to elicit superoxide anion production and lysozyme release, while slight, but not statistically significant activity was induced in chemotaxis. The role of the orientation of the aromatic ring with respect to the backbone adjacent atoms is discussed.
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PMID:Modified chemotactic peptides: synthesis, conformation, and biological activity of For-Thp-Leu-delta ZPhe-OMe. 794 17

We have measured the metabolic stabilities of wild-type and 17 temperature-sensitive mutants of T4 lysozyme in HeLa cells, in Xenopus egg extract, and in reticulocyte lysate. [35S]Methionine-labeled T4 lysozymes were expressed in Escherichia coli, purified, injected into HeLa cells, and their degradation rates were determined. Wild-type T4 lysozyme has a half-life of 4 h; the half-lives of 16 lysozyme variants ranged from 2 to 10 h. Surprisingly, the most temperature-sensitive enzyme in the set, R96H, was significantly more stable (half-life = 10 h). Different T4 lysozyme variants yield conflicting answers to the proposed relationship between thermal and metabolic stabilities. For mutations at Thr157 there is no correlation between melting temperature and half-life. By contrast, T4 lysozymes mutated at various positions show a definite correlation between the two parameters. Treatment of injected HeLa cells with the lysosomotropic agents chloroquine or ammonium chloride did not alter the stability of T4 lysozyme. However, the enzyme's half-life increased 10-fold in HeLa cells depleted of ATP. Although T4 lysozyme is degraded rapidly within HeLa cells, the molecule is stable in reticulocyte lysate and Xenopus egg extract. Presumably, there is a specific proteolytic event(s) in HeLa cells which is not manifest in the in vitro extracts.
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PMID:On the relationship between the metabolic and thermodynamic stabilities of T4 lysozymes. Measurements in eukaryotic cells. 796 93

Isolated alveolar type II pneumocytes of the rat have been shown to secrete a 14 to 15 kD protein that has some sequence homology and immunoreactivity with lysozyme. Using immunochemical analyses of rat lung subcellular fractions and 35S metabolic labeling of isolated perfused lung preparations, we studied the subcellular distribution and synthetic pathway for this protein. SDS-PAGE and Western blotting of lamellar bodies (LB) using a polyclonal anti-human lysozyme (anti-HLZ) demonstrated a single band at 15 kD that was significantly enriched over rat lung homogenates, isolated lysosomes, and type II cell lysates. This 15 kD protein isolated from LB by immunoprecipitation with anti-HLZ also demonstrated functional lysozyme activity and was termed lamellar body lysozyme (lbl-15). Analysis of LB and surfactant (SF) isolated from 12 separate perfused lung preparations labeled for 6 h with 35S-labeled amino acids demonstrated that lbl-15 represented a significant portion of the radiolabeled LB proteins (5.9% of total LB radioactivity). Lamellar bodies and an extracellular fraction (surfactant) obtained from rat lungs perfused with 35S-methionine-cysteine for varying times both showed time-dependent appearance of lbl-15. At all time points, the specific activity of lbl-15 was greater in LB than in SF. The kinetics for appearance of lbl-15 in LB and SF was similar to that for surfactant protein A. These results indicate that in the rat lung, type II cells synthesize a 15 kD protein (lbl-15) that is secreted into the alveolar space via an organellar pathway involving LB.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Synthesis of type II cell lamellar body lysozyme-15 kD protein (lbl-15) by perfused rat lung. 804 85


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