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 protein adsorptive properties of monosodium urate monohydrate (MSU), silica (Si), and calcium pyrophosphate dihydrate crystals were studied by qualitative and quantitative techniques. Immunoglobulin G (IgG) was adsorbed preferentially by MSU crystals from normal human serum and demonstrated high-affinity binding isotherms when compared with several isolated proteins in solution. The physical characteristics of this reaction suggest principally an ionic mechanism, since adsorption was enhanced by decreasing pH or ionic strength. Weaker physical forces also were suggested by studies showing enhanced adsorption at lower temperatures. The following order of affinity for Si or MSU crystals was found when equal concentrations of proteins were compared: Cohn fraction II greater than lysozyme greater than beta lactoglobulin greater than bovine serum albumin greater than ovalbumin. IgG adsorption to the crystals studied may explain certain features of their biological activity. It is suggested that this phenomenon blocks the membranolytic properties of crystals and stimulates their phagocytosis through interaction with Fc receptors on the surface of the phagocytic cells.
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PMID:Protein binding to monosodium urate monohydrate, calcium pyrophosphate dihydrate, and silicon dioxide crystals. I. Physical characteristics. 1 76

The thermal perturbation difference spectrum of reduced lysozyme has a long wave length extremum at 304 nm at pH 6.15 and a very small extremum at 306 nm at pH 1.5. These results differ from those of Leach & Smith (1972), which showed an extremum at 293 nm, the same as for model tryptophyl compounds. Our result may arise from a conformational difference between the two sample temperatures. The interpretation of thermal perturbation spectra of proteins is discussed. Contributions from thermally induced concentration differences, buried chromophores, and chromophores in crevices are considered in the interpretation of the thermal perturbation spectrum of bovine serum albumin. It is suggested that chromophores in pauci-aqueous crevices may appear buried toward thermal perturbation spectroscopy but accessible toward solvent perturbation and chemical reagents.
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PMID:Interpretation of thermal perturbation spectra of proteins. 1 20

Washed, preincubated minced hen's oviducts, which contained low levels of extracellular and intracellular proteins, synthesized egg-white proteins actively. The addition of ovalbumin to the incubation medium resulted in inhibition of the synthesis of egg-white proteins by the washed, preincubated oviduct cells, while the addition of bovine serum albumin seemed to stimulate protein synthesis and hen's egg-white lysozyme had no effect. The inhibitory or stimulatory effect on protein synthesis was proportional to the amount of protein added to the medium. The inhibitory effect of added ovalbumin was shown not to be due to the incorporation of ovalbumin into the oviduct cells from the incubation medium. Egg-white proteins added to the medium also inhibited protein synthesis inside the cells and the extent of the inhibition appeared to correspond to the amount of ovalbumin present in egg-white.
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PMID:Regulation of protein synthesis in hen's oviducts. II. Extracellular ovalbumin as an inhibitor of ovalbumin synthesis in the oviducts. 1 47

Reactions of proteins with dehydroalanine or derivatives of dehydroalanine were studied as models for protein crosslinking. Treatment of casein, bovine serum albumin, lysozyme, wool or polylysine with acetamido- and phenylacetamido acrylic acid methyl esters at pH 9-10 converted varying amounts of lysine to lysinoalanine residues. Howver, complete transformation was not achieved. Incomplete reaction is atributed to partial hydrolysis of the esters to the less reactive acrylic acids under the reaction conditions. Similar studies were made of the reactivities of protein SH groups generated by reduction of disulfide bonds by tributylphosphine. The SH groups could be completely alkylated at pH 7.6 in aqueous propanol, as shown by nearly quantitative recovery of lanthionine. Such a procedure might therefore be used to estimate cystine contents of proteins.
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PMID:Reactions of proteins with dehydroalanines. 2 Jul 47

A model system of ontogeny was utilized to investigate the development of humoral immunity in both AKR and BALB/c mice. Lethally irradiated adult mice were reconstituted with syngeneic fetal or neonatal liver. These mice were immunized at various times after reconstitution with a series of eight antigens: the bacteriophages F2, phiX-174, and T4; the hapten carrier complexes 2,4 dinitrophenyl-bovine serum albumin and fluorescein-bovine serum albumin; and the small proteins: hen egg lysozyme, sperm whale myoglobin, and bovine pancreatic ribonuclease. Subsequent antibody production to the antigens was assayed with either a direct or a modified bacteriophage neutralization technique. Individual mice responded to the various antigens in a sequential pattern which was basically the same for all mice within each strain. However, there was a marked difference between the two strains in the time at which they developed responsiveness to myoglobin. In order to begin to delineate the separate roles played by B and T cells in the generation of this hierarchical response pattern during ontogeny, the development of anti-DNP and anti-FTC activity was examined in carrier-primed mice. Results of this experiment indicated that functional B cell specificities for the two haptens arise at different times during ontogeny. Further studies are needed to determine whether the hierarchical pattern of immune responsiveness observed for the other antigens is a function of sequential appearance of B cell specificities, T cell specificities, or both.
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PMID:Determinants of the hierarchy of humoral immune responsiveness during ontogeny. 5 70

From experiments with glycoproteins containing the glycopeptide linkages, arabinose-O-hydroxyproline and galactose-O-serine (plant cell wall glycopeptides), N-acetylgalactosamine-O-serine/threonine (pig submaxillary mucin), and N-acetyl-glucosamine-N-asparagine (fetuin), it is apparent that anhydrous liquid HF, a reagent commonly used by snythetic peptide chemists for the complete removal of protecting groups from synthetic peptides, cleaves the O-glycosidic linkages of neutral sugars in 1 hr at 0 degrees C, and the O-glycosidic linkages of amino sugars in 3 hr at 23 degrees C. The N-glycosidic linkage of N-acetylglucosamine to asparagine is not cleaved under any conditions that have been tested. Sodium dodecyl sulfate gel electrophoresis of bovine serum albumin treated in HF does not show any degradation of peptide bonds. Some relatively stable enzymes (lysozyme and RNase) have been shown by others to retain most of their enzymic activity after short treatment (1 hr at 0 degrees C) in HF. With the specificity of HF at 0 degrees C for neutral sugars it should be possible to generate di- or trisaccharides in high yield from polysaccharides containing both neutral and amino sugars with neutral sugars as the reducing termini.
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PMID:A new approach to the structural determination of glycoproteins and polysaccharides: anhydrous HF solvolysis. 7 2

Following fixation with formalin or glutaraldehyde, the protein content of bovine serum albumin, lysozyme, non-disintegrated yeast cells and liver nuclei of mice is determined by means of a brom-phenol blue staining procedure and the widely used Lowry-technique. The bromphenol blue technique permits determinations of soluble as well as particulate proteins or protein mixtures fixed with up to 6% formalin or 2% glutaraldehyde. Recovery rates differ no more than 20% as related to unfixed controls. Using the bromphenol blue method it is not necessary to separate aldehyde or any interfering material by additional steps prior to determination. Factors for correcting protein content of biological material after aldehyde treatment are available. In this way, comparative biochemical as well as cyto- and histochemical investigations of enzymatic activities after aldehyde fixation are possible. Some advantages of the bromphenol blue technique with special reference to the analysis of particulate and/or aldehyde-fixed specimens are discussed.
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PMID:[Essay of proteins after aldehyde treatment in biological objects (author's transl)]. 8 Sep 8

Heat-denatured chicken egg white lysozyme and the reduced carboxymethylated maleylated derivative of this protein were found to serve as substrates for rabbit skeletal muscle cyclic AMP-dependent protein kinase. The native form of the protein was not a substrate. Two phosphoryl groups per mole of lysozyme were incorporated in the reaction. It was determined that the phosphoryl moieties were bound to serine 24 and serine 50 in the modified protein. Serine 24 was phosphorylated approximately 3 times as fast as serine 50. Reduced carboxymethylated maleylated derivatives of bovine serum albumin, phosphorylase b, and creatine kinase also served as substrates for the protein kinase whereas their native forms did not. The reduced carboxymethylated maleylated derivative of the inhibitory subunit of troponin was a poorer substrate than the native form of the protein. Maleylated histones F1 and F2b were also poorer substrates than the nonderivatized forms. The significance of these experiments with reference to the specificity of cyclic AMP-dependent protein kinase is discussed.
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PMID:Effect of denaturation on the susceptibility of proteins to enzymic phosphorylation. 16 38

The specifity of Ag+ ions for protein SH groups has been questioned frequently, even though the amperometric titration with AgNO3 is one of the most common methods for the determination of SH groups in proteins. This is due to the fact, that the formation of silver complexes in the titration of cysteine causes a consumption of AgNO3 which is too high. In order to find out if this may be true in the case of proteins, in the present work select proteins with a well known content of SH and SS groups have been titrated amperometrically in tris buffer pH 7.4 with 0.001 M AgNO3. The proteins used were hemoglobin, bovine serum albumin, ovalbumin, lysozyme, pepsin, myoglobin, and cytochrome c. The direct and the indirect titrations of (a) native, (b) denatured, and (c) NaBH4 reduced proteins showed, that the expected consumption of AgNO3 was in no case exceeded. Therefore under the conditions used AgNO3 may be considered as a specific reagent for protein SH groups. High SH values as a result of the amperometric titration of proteins with silver nitrate, which have been published occasionally, may be due to incorrect estimation of the end point of the titration. The reducibility of SS groups depends on the kind of protein. Lysozyme and pepsin were already completely reduced at 23 degrees C, whereas bovine serum albumin needed 60 degrees C. The direct titration method was useful only in some cases for the detection of all SH groups originally present in the proteins or formed by reduction with NaBH4. On the other hand the indirect titration method gave maximum values, because the slowly reacting SH groups of proteins are also allowed to react and the resulting titration curves may be evaluated correctly.
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PMID:[Determination of sulphydryl and disulphide groups in proteins by amperometric titration. III. Investigation of the specifity of Ag+ ions for protein SH groups (author's transl)]. 17 21

The protein spin-echo decay and recovery of longitudinal magnetization were studied in seven globular proteins: cytochrome C, ribonuclease, lysozyme, DNA, hemoglobin, serum albumin and gamma-globulin in D2O solutions. For comparison the Tobacco mosaic virus (TMV) protons in D2O solutions were also investigated. The spin-echo decay of all 7 proteins can be separated into three components: a slowly decaying component with an amplitude of about 10% of the amplitude of the total signal, intermediately and fastly decaying components, the two latter being comparable in amplitudes. Longitudinal relaxation is more simple in character. The value of T2 of the protons responsible for the fastly decaying components in linearly dependent on the molecular weight of the protein, a fact indicating that the regions of the proteins with a "rigid" structure can be responsible for this component. The intermediate component, whose contribution increases with temperature, was ascribed to the mobile regions of the protein, and the slowly decaying component to the mobile protein side chains. Weak dependence of T1 on the protein molecular weight and some other obtained data give additional evidence for the presence of motion within macromolecules. The peculiarities of this motion is in good correspondence with the notion about the existence of the segmental motion of the polypeptide chain (conformational mobility of the protein). In contrast to proteins the spin-echo decay of TMV lacked the slow component and the "solid" echo signal was observed which indicates the existence of a "rigid" structure in the macromolecules of the virus.
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PMID:[Study of the conformational mobility of globular proteins by pulse methods of NMR]. 20 75


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