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)

The first example of a chicken cDNA sequence encoding a phosphotyrosyl phosphatase (PTPase) has been identified and found to contain coding sequences for the entire cytoplasmic and membrane spanning domains as well as a portion of the extracellular region of a transmembrane PTPase resembling human PTP zeta. Like HPTP zeta, chicken PTP zeta contained two phosphatase domains (D1 and D2), and D2 lacked a critical cysteine residue required for catalytic activity. The entire intracellular portion of CPTP zeta was expressed in bacteria and shown to be capable of dephosphorylating both p-nitrophenylphosphate and reduced carboxyamidomethylated and maleyated lysozyme but not phosphoseryl casein. Genetic analysis indicated that the presence of D2 was required for full activity. CPTP zeta mRNA was identified as a single large transcript expressed exclusively in the brain of chick embryos at both early and late stages of embryogenesis. These results suggested that CPTP zeta may perform a brain-specific function and have a role in development.
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PMID:Isolation of chicken phosphotyrosyl phosphatase cDNA sequences and identification of a brain-specific species related to human PTP zeta. 829 38

The major proteins in the lumen of the endoplasmic reticulum (ER) are thought to function in Ca2+ sequestration or as "molecular chaperones" in the folding and assembly of membrane or secreted proteins. Based on the ability of many chaperones to bind selectively to unfolded proteins and to dissociate from them upon ATP hydrolysis, we developed an affinity chromatography method to isolate proteins with these characteristics from pancreatic or liver ER. Seven ER proteins bound selectively to denatured protein columns and were specifically eluted by ATP (10(-6) M) but not by a nonhydrolyzable ATP analog. These proteins were identified with antibodies and microsequencing as the ER chaperone BiP (grp78), grp94, calreticulin, a novel 46-kDa protein that binds azido-ATP, as well as three members of the thioredoxin superfamily: protein-disulfide isomerase, ERp72, and a previously reported 50-kDa protein (p50). This set of seven proteins bound to and was eluted with ATP from a variety of denatured proteins, including histone, gelatin, alpha fetoprotein, thyroglobulin, lysozyme, casein, and IgG. The release of grp94, protein-disulfide isomerase, ERp72, calreticulin, and p50 was stimulated by Ca2+ in the presence of ATP. These proteins thus appear to function as Ca(2+)-dependent chaperones, which may account for the Ca2+ and ATP requirement for protein folding in the ER.
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PMID:A set of endoplasmic reticulum proteins possessing properties of molecular chaperones includes Ca(2+)-binding proteins and members of the thioredoxin superfamily. 829 23

Stimulation of fibroblasts with serum growth factors results in the rapid activation of a set of immediate-early genes, among them 3CH134. We have purified a bacterially expressed form of the 3CH134-encoded polypeptide and demonstrated that it has intrinsic protein-tyrosine-phosphatase (PTPase; protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48) activity in vitro. This activity is optimal at pH 7.5, is sensitive to vanadate and cysteinyl modifying agents, and is insensitive to a panel of serine/threonine phosphatase inhibitors. Purified 3CH134 protein displays a high degree of selectivity among the tyrosine-phosphorylated polypeptide substrates tested. Under our assay conditions, the rates of dephosphorylation are in the order EDNDYINASL peptide < myelin basic protein < reduced, carboxyamidomethylated, and maleylated lysozyme (RCML) < p42mapk. There is a 200-fold range in rates for these substrates, with p42mapk dephosphorylated 15-fold more rapidly than RCML. Although 3CH134 is most closely related to the tyrosine/serine dual-specificity phosphatase VH1, we failed to detect any 3CH134-directed activity on casein or RCML phosphorylated on serine/threonine residues by cAMP-dependent protein kinase. Since 3CH134 expression is controlled transcriptionally and posttranscriptionally, it may represent a class of PTPases whose activity is regulated at the level of protein synthesis and degradation.
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PMID:The growth factor-inducible immediate-early gene 3CH134 encodes a protein-tyrosine-phosphatase. 838 79

We have detected a protein phosphatase activity in soluble extracts from the halophilic archaeon Haloferax volcanii. This activity was markedly stimulated by the divalent metal ions Mn2+ and Cd2+. It dephosphorylated phosphoseryl residues in casein, mixed histones, and phosphorylase a, but not phosphotyrosyl residues in reduced, carboxyamidomethylated and maleylated lysozyme. This protein phosphatase activity was inhibited by NaF, Zn2+, vanadate, molybdate, inorganic phosphate, inorganic pyrophosphate, or p-nitrophenyl phosphate, or by treatment with diethylpyrocarbonate. Activity was unaffected by other potential inhibitors or activators such as polyamines, heparin, cyclic nucleotides, Ca2+/calmodulin, tartrate, tetramisole, okadaic acid, microcystin LR, or sulfhydryl-modifying agents. The functional similarities between this protein-serine phosphatase and that previously identified in another archaeon, the extreme acidothermophile Sulfolobus solfataricus, suggest the existence of a family of divalent metal ion-stimulated protein-serine phosphatases of extremely ancient origin in the Archaea.
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PMID:A protein-serine phosphatase from the halophilic archaeon Haloferax volcanii. 839 5

MDA-modified casein, lysozyme or polylysine (MC, ML and MP respectively), was intradermically injected to rabbits in the presence of complete Freund's adjuvant (cFA). Two other animal sets received either cFA alone, or MDA alone. MDA, cFA and MP did not induce any antibody response. Both ML and MC produced an increase of antibody reactivity towards ML, but reactivity towards native lysozyme (L) was increased only by ML and not by MC. According to these results, it was concluded that the epitopes recognized by antibodies reacting with ML and not with L are AIP bridges and possibly the two surrounding aminoacyl (especially lysyl) residues.
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PMID:Immunization of rabbits with proteins reacted with malonic dialdehyde (MDA): kinetics and specificity of the immune response. 849 May 60

Cell envelopes of Bacillus cereus contain a casein-cleaving membrane proteinase (CCMP) and an insulin-cleaving membrane proteinase (ICMP), which differ in their substrate and inhibitor specificity from all Bacillus proteinases described previously. They remained localized in the cytoplasmic membrane after treatment with lysozyme and mutanolysin and they are strongly attached to the membrane compared with other known membrane proteinases. Only high a concentration of the Zwitterionic detergent sulfobetain SB-12 enabled an effective solubilization of both membrane proteinases. The usual conventional purification methods, such as chromatofocusing, ion-exchange chromatography and hydrophobic interaction chromatography in the presence of detergent concentrations beyond their critical micelle concentration, could not be applied to the purification, because the solubilized membrane proteinases bound strongly and irreversibly to the chromatographic matrix. In the search for other purification methods, we used a tentacle ion-exchanger (EMD trimethylaminoethyl-Fractogel) to reduce the hydrophobic interactions between the proteinases and the matrix. All contaminating proteins could be removed by a first gradient of sodium chloride without elution of CCMP; a second gradient with isopropanol and a decreasing salt concentration resulted in an efficiently purified CCMP. The ICMP was irreversibly denaturated. Purified CCMP is a member of the metalloproteinase family with a pH optimum in the neutral range and a temperature optimum of 40 degrees C, whose properties differ from the serine-type membrane proteinase of Bacillus subtilis described by Shimizu et al. [Agric. Biol. Chem., 47 (1983) 1775]. It consists of two subunits in sodiumdodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions (Mr 53,000 and 65,000); however, the molecular mass of the purified enzyme could not be determined by size exclusion or SDS-PAGE, because the purified enzyme aggregated at the top of the gel matrix. CCMP solubilized before the purification process, could be eluted in the presence of 0.1% octylphenol-poly(ethyleneglycol ether)9-10 (Triton X-100) in two peaks of Mr 56,000 and 128,000, respectively. We discuss this special chromatographic behaviour of the CCMP from Bacillus cereus, with regard to the strong hydrophobic interactions of the enzyme with the chromatographic matrix and additional self-aggregation, which could only be dissolved by solvents such as isopropanol.
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PMID:Unusual chromatographic behaviour and one-step purification of a novel membrane proteinase from Bacillus cereus. 852 Jun 70

A ubiquitin (Ub)/ATP-dependent proteolytic complex (26S proteasome) purified from rabbit skeletal muscle was dissociated into two subcomplexes, a 20S proteasome and a regulatory subunit complex, by preparative non-denaturing polyacrylamide gel electrophoresis (PAGE). The isolated regulatory subunit complex preparation gave a single broad band on analytical non-denaturing PAGE, and several bands ranging between 33 and 110 kDa on SDS-PAGE. This complex was found to consist of about 20 subunits on the basis of two-dimensional PAGE, the pattern of which appeared identical or very similar to that of the 33-110 kDa 26S proteasome subunits. The apparent molecular mass of the complex was estimated to be 1100 kDa by Ferguson plot analysis and also by Superose 6 gel filtration. Unlike the 26S proteasome, neither ATPase activity nor protease activities toward Suc-Leu-Leu-Val-Tyr-MCA, Boc-Phe-Ser-Arg-MCA, Z-Leu-Leu-Glu-beta NA, [14C]-casein, [125I]-lysozyme and Ub-[125I]-lysozyme were significantly detectable in the regulatory subunit complex. This complex was found to be capable of associating with itself in MgATP-dependent manner. These results suggest that a regulatory subunit complex dissociated from the 26S proteasome comprises all the higher molecular mass subunits of the 26S proteasome, and has no detectable ATPase and protease activities, although the homo-oligomerization occurs in an ATP-dependent fashion.
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PMID:Regulatory subunit complex dissociated from 26S proteasome: isolation and characterization. 854 9

One hundred twenty male Sprague-Dawley rats (3 weeks old) were given biotin-deficient diets containing ovalbumin as the protein source. Ten control rats of the same origin were fed a commercially available purified diet that used casein as a protein source. Eosinophils and histiocytes were observed at a higher frequency in lungs of rats fed the purified diets containing ovalbumin than in the controls. Foam cells were confined to subpleural and peribronchial regions, reacting positively to anti-lysozyme antibody. The incidence of pulmonary histiocytosis was 76/120 rats (63.3%) in the groups fed the ovalbumin-containing diets as compared with 1/10 (10.0%) in the controls. The accumulation of eosinophils in lung was highest (6/24 rats, 25%) at 3 months. This lesion was not seen in the controls. Eosinophils were first observed in the perivascular and peribronchiolar regions. In advanced lesions, macrophages and mast cells also appeared in the lesions, which at this stage resembled so-called idiopathic chronic eosinophilic pneumonia of human beings. Neither foam cells nor eosinophils were present in any of the other organs. Because there was no difference in the composition of the diets with the exception of the protein source, these lung lesions may be due to biotin deficiency resulting from the use of ovalbumin as the protein source.
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PMID:Eosinophil and foam cell accumulation in lungs of Sprague-Dawley rats fed purified, biotin-deficient diets. 857 40

A method for the quantitative determination of lysine, histidine and tyrosine in foods based on pre-column derivatization with 5-dimethylaminonaphthalene-1-sulfonyl chloride (DnsCl) and reversed-phase liquid chromatography has been developed. Derivatization conditions, including DnsCl concentration, time, temperature, and buffer solution were studied. To establish the reliability of the proposed liquid chromatographic (LC) method, the precision and accuracy of the analyses were evaluated using samples of casein and lysozyme.
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PMID:Isocratic high-performance liquid chromatographic method for quantitative determination of lysine, histidine and tyrosine in foods. 858 28

Transgenic mice were used as model systems to evaluate the impact of human lysozyme expression in the mammary gland. We previously generated two lines of transgenic mice that express human lysozyme mRNA in the mammary gland under the tissue-specific and developmentally correct control of the bovine gene promoter for alpha s1-casein. Concentrations of human lysozyme protein in milk of transgenic mice varied from .25 to .71 micrograms/microliters of milk. Human lysozyme secreted into mouse milk retained its antimicrobial activity, as determined by a denaturing polyacrylamide gel activity assay. The physical and functional properties of the milk were also altered, because mouse milk containing human lysozyme had a 35% decrease in rennet clotting time, a smaller median micelle size (157 nm vs. 172 nm), and a 2.5- to 3-fold greater gel strength than control milk. From these results, we conclude that the use of transgenic animals producing lysozyme in the milk is feasible and potentially useful to the dairy industry.
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PMID:The effect of mammary gland expression of human lysozyme on the properties of milk from transgenic mice. 867 51


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