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)

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

Activated human polymorphonuclear leukocytes (PMN) isolated from peripheral blood specifically bind 125I-laminin after stimulation with phorbol 12-myristate 13-acetate (PMA) or f-Met-Leu-Phe (FMLP) at 37 degrees C. Changes in laminin receptor expression are stimulus dose dependent at both chemotactic (10(-10) M to 10(-6) M) concentrations of FMLP, and secretory (greater than 5 ng/ml) levels of PMA. In the presence of cytochalasin B (5 micrograms/ml), 10(-7) M FMLP activation stimulates specific laminin binding, with an apparent Kd = 3.9 X 10(-9) M and 6.47 X 10(5) binding sites/cell, reaching equilibrium within 10 min at 4 degrees C. This observed activation-dependent change in laminin receptor expression is not due to interference by endogenous laminin, because no fluorescein-visualized anti-laminin antibody bound to cells without added glycoprotein, regardless of the level of activation. Levels of neutrophil lysozyme release, which show a PMA dose dependence similar to that of receptor binding activity, suggest that granule-plasma membrane fusion may be significant during increases in receptor expression. A lack of receptor stimulation by PMA from a granule-deficient patient or in granule-depleted cytoplasts from normal donors additionally supports this hypothesis. Electroblot transfer and autoradiography of subcellular fractions from unstimulated PMN reveals the presence of a 68,000 dalton laminin-binding component in the secondary/tertiary granule (beta) fraction, which may represent an intracellular laminin receptor pool.
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PMID:Human neutrophil laminin receptors: activation-dependent receptor expression. 294 78

Two mouse monoclonal antibodies, L12.2 and S5.22, were developed that are specific for human neutrophilic granulocytes and produce a twofold to threefold stimulation of n-formyl-methionine-leucyl-phenylalanine (FMLP)-induced chemotaxis. Stimulation of chemotaxis by the antibodies is specific for FMLP and is concentration dependent. L12.2 appears to be more potent in stimulating chemotaxis and is isotypically distinct from S5.22. In addition, although L12.2 reacts only with mature peripheral blood granulocytes, S5.22 reacts with leukemic cells of both myeloid and monocytic origin and with immature granulocyte precursor cells. This suggests that L12.2 interacts with an antigen that appears late in the differentiation pathway, whereas S5.22 binds to an antigen that is present throughout the myeloid lineage. By means of the under-agarose and Boyden chamber techniques, L12.2, but not S5.22, by itself was also found to be a potent granulocyte chemoattractant. Cells in a gradient of L12.2 display polarized and oriented morphology. L12.2 alone, but not S5.22, also stimulates granulocyte phagocytosis and induces superoxide anion production. Neither L12.2 nor S5.22 affected the release of myeloperoxidase or lysozyme from granulocytes either alone or in combination with FMLP, C5a, or the tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). These results suggest that L12.2 interacts with a single antigenic determinant on granulocytes that is involved in chemotaxis, phagocytosis, and superoxide anion release.
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PMID:Stimulation of human neutrophilic granulocyte chemotaxis by monoclonal antibodies. 298 Dec 60

Reductive alkylation of lysyl epsilon-amino groups with sugars (1-deoxyglycitolation) using pyridine borane as the reducing agent has been recently described [Wong, W.S.D., Osuga, D.T. & Feeney, R.E. (1984) Anal. Biochem. 139, 58-67]. The regeneration of the lysines has now been achieved by oxidation with approximately 10 mM periodate. In experiments with glycitolated bovine serum albumin, reactions using 5, 20, and 80 mM periodate were essentially complete in the first 10 min. Oxidations of methionine to the sulfoxide were evident even at this lower concentration of periodate, while higher concentrations and prolonged reaction times only caused unnecessary destruction of amino acids. The removal was shown to occur in a wide pH range with little variation in the recovery of the lysines. The degree of glycitolation, or the nature of the attached carbohydrate residues, had no effect on the yield of products. Reductive 1-deoxygalactitolation of approximately 55% of the lysyl epsilon-amino groups of lysozyme caused no loss in enzymatic activity; when 5 mM periodate was used to remove the 1-deoxygalactitol moiety, approximately 95% of the amino groups were regenerated, concomitant with destruction of approximately 16% of the activity. On reductive 1-deoxygalactitolation of the amino groups of turkey ovomucoid, 65% of the lysyl epsilon-amino groups were modified with 70% loss of the inhibitory activity against trypsin. On treatment with 5 mM periodate, approximately 80% of the amino groups were regained with a similar recovery of the inhibitory activity.
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PMID:1-Deoxyglycitolation of protein amino groups and their regeneration by periodate oxidation. 299 56

Wild-type and amber mutant alleles of the lysis genes of P22 were cloned and sequenced. Gene 13 encodes an 11,520-Da basic hydrophobic protein that has 89% amino acid homology to lambda S protein. Gene 19 encodes a protein that has a small degree of amino acid homology with T4 lysozyme, but we could detect no homology to lambda R or RZ proteins. The protein product of gene 19 was purified; its amino terminal amino acid sequence is as predicted by the DNA sequence. It starts with a single amino terminal methionine residue and is a basic protein with a molecular weight of 15,968. Plasmids expressing P22 gene 19, lambda genes R and RZ, and T4 gene e were constructed. All of these plasmids were able to complement both lambda R- and P22 19-.
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PMID:Phage P22 lysis genes: nucleotide sequences and functional relationships with T4 and lambda genes. 299 5

The secretory response of cytochalasin B-treated human polymorphonuclear neutrophils to the peptide chemoattractant f-Met-Leu-Phe (FMLP), the calcium ionophore A23187 and other secretagogues was measured by assaying neutrophil supernatants for the granular enzymes beta-glucuronidase and lysozyme. The dose-dependent enzyme secretion in response to 10(-8)-10(-4) M FMLP and A23187 was unaffected by pretreatment with 10-75 microM forskolin (an activator of adenylate cyclase), but inhibited by high concentrations of prostaglandins E1 and E2. The phosphodiesterase inhibitors isobutyl-methyl-xanthine (IBMX), papaverine and Ro 20-1724 dose dependently inhibited enzyme secretion from FMLP- or A23187-treated cells, and this effect was augmented in the presence of 50-75 microM forskolin. Similar results for PGE1, forskolin and forskolin/IBMX combinations were also obtained using leukotriene B4, platelet activating factor and C5a des-Arg as secretagogues. We conclude that the adenylate cyclase system of human neutrophils is activatable by forskolin, but that the regulatory effects of adenylate cyclase stimulants in these cells are greatly attenuated unless cyclic AMP-phosphodiesterases are inhibited. Thus the phosphodiesterase activity of neutrophils may be of functional importance and is relevant to the modulation of neutrophil activity in inflammation.
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PMID:Inhibition of human neutrophil degranulation by forskolin in the presence of phosphodiesterase inhibitors. 301 41

Oxidative metabolism of polymorphonuclear leukocytes (PMNLs) isolated from pregnant women in the third trimester and from controls were studied using zymosan-induced chemiluminescence (CL) and f-Met-Leu-Phe-stimulated superoxide (O2-) generation. CL was significantly increased during pregnancy, but a decrease was noted in cytochrome c reduction. Total cellular levels of beta-glucuronidase and lysozyme were diminished in PMNLs from pregnant subjects, with unaltered concentrations of cytosol lactate dehydrogenase. The capacity of PMNLs from pregnant women to degranulate did not differ from controls. It is suggested that during pregnancy, in vivo stimulation of PMNLs may occur to account for these changes.
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PMID:Polymorphonuclear leukocyte response to stimulation in vitro during pregnancy. 301 55

Human granulocyte-macrophage colony stimulating factor (GM-CSF) has been synthesized in high yield using a temperature inducible plasmid in Escherichia coli. The human GM-CSF is readily isolated from the bacterial proteins because of its differential solubility and chromatographic properties. The bacterially synthesized form of the human GM-CSF contains an extra methionine residue at position 1, but otherwise it is identical to the polypeptide predicted from the cDNA sequence. The specific activity of 2.9 X 10(7) units/mg of protein for purified bacterially synthesized human GM-CSF indicates that despite the lack of glycosylation, the molecule is substantially in its native conformation. This molecule stimulated the same number and type of both seven- and 14-day human bone marrow colonies as the CSF alpha preparation from human placental conditioned medium. Human GM-CSF had no activity on murine bone marrow or murine leukemic cells. There was no detectable, direct stimulation of adult human erythroid burst forming units (BFU-E) by the bacterially synthesized human GM-CSF. Although impure preparations containing native human GM-CSF (eg, human placental conditioned medium) stimulated the formation of mixed colonies, even in the presence of erythropoietin, the bacterially synthesized human GM-CSF failed to stimulate the formation of mixed colonies from adult human bone marrow cells. The bacterially synthesized human GM-CSF increased N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced superoxide production and lysozyme secretion. Antibody-dependent cytotoxicity and phagocytosis by human neutrophils was stimulated by the bacterially synthesized human GM-CSF and eosinophils were also activated in the antibody-dependent cytotoxicity assay.
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PMID:Purification and properties of bacterially synthesized human granulocyte-macrophage colony stimulating factor. 302 61

Anacystis nidulans 6301 has been transformed in the light to ampicillin resistance with the plasmid pBR322. Permeaplasts prepared by 2-hr treatment of cells with lysozyme and EDTA are transformed with a 50-fold higher efficiency than that observed for cells. beta-Lactamase is present in A. nidulans transformed either with pBR322 or the plasmid pCH1 as evidenced by hydrolysis of the beta-lactam ring of Nitrocefin in extracts of transformants. beta-Lactamase also can be immunoprecipitated from extracts of [35S]methionine-labeled pBR322 transformants and coprecipitates with ribulose-bisphosphate carboxylase. Expression of the carboxylase is apparently amplified in pBR322 transformants as is that for several soluble proteins in pCH1 transformants. Chromosomal DNA per cell is increased about 6-fold after transformation of A. nidulans 6301 with either pBR322 or pCH1. A 4.3-kilobase-pair plasmid can be isolated from pBR322 transformants in addition to the endogenous plasmids pUH24 and pUH25.
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PMID:Transformation of the cyanobacterium Anacystis nidulans 6301 with the Escherichia coli plasmid pBR322. 308 98

The interaction of synthetic peptides corresponding to the signal sequences of Escherichia coli alkaline phosphatase: Lys-Gln-Ser-Thr-Ile-Ala-Leu-Ala-Leu-Leu-Pro-Leu-Leu-Phe-Thr-Pro-Val-Thr- Lys-Ala - OCH3, chicken lysozyme: Met-Lys-Ser-Leu-Leu-Ile-Leu-Val-Leu-Cys(Bzl)-Phe-Leu-Pro-Leu- Ala-Ala-Leu-Gly-OCH2-C6H5 and variant of the chicken lysozyme signal sequence with a charged residue in the hydrophobic region: Lys-Leu-Leu-Ile-Ala-Leu-Val-Leu-Lys-Phe-Leu-Pro-Leu-Ala-Ala- Leu-Gly-OCH3 with model membranes of brain phosphatidylserine (PS) and egg phosphatidylcholine (PC) have been investigated by 90 degrees light scattering and fluorescence spectroscopy. Our results indicate that the association of signal peptides with model membranes results in extensive perturbation of the lipid bilayer so as to cause fusion of PS vesicles and aggregation of PC vesicles. The vesicles are also rendered permeable to hydrophilic molecules like carboxyfluorescein. The variant peptide with the lysine residue in the hydrophobic region also has the ability to perturb lipid bilayers of model membranes.
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PMID:Perturbation of the lipid bilayer of model membranes by synthetic signal peptides. 331 Nov 64


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