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)

1. A cationic protease has been purified from the granule fraction of blood-donor leukocytes by a preparative method including precipitation by acetone and chromatography on Bio-Gel A 1.5 m, CM-Sephadex C-50 and Sephadex G-G-75. 2. The pH optimum against denatured bovine hemoglobin is 7.4. Gel chromatography indicated a molecular weight close to 23 000. 3. This neutral protease (EC 3.4.-.-) is able to split the synthetic esters Z-Ala-NPh and AcAla3OMe, its activity on the former substrate being 2.2 times greater than that of pancreatic elastase, on the latter the same. It differs crucially from pancreatic elastase in having small elastinolytic activity. 4. In cationic disk electrophoresis, neutral protease resolves into three protein bands with lower mobility than lysozyme: all bands exhibit esterolytic activity against 2-acetoxy-3-naphthoic acid o-toluidide, strongly suggesting that they represent isoenzymes. 5. The enzyme is completely inhibited by iPr2P-F, partially so by soybean trypsin inhibitor and Trasylol. Cysteine, EDTA and TosLysCH2Cl have no effect. 6. During chromatography on CM-Sephadex C-50 a more positively charged enzyme(s) was identified. This had hemoglobinolytic activity at pH 7.4 but only a small esterolytic effect on Z-Ala-NPh; it showed only traces of activity against AcAla3OMe.
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PMID:Purification and some properties of a neutral protease from human leukocyte granules and its comparison with pancreatic elastase. 0 9

Earlier studies on fetal thymus suggested that certain of the large pyroninophilic cells found there might have a hemopoietic role, and it was decided to determine the nature of these cells using histochemical and immunohistochemical methods. Thymic tissue from aborted fetuses, stillbirths, and neonatal deaths was examined histochemically using methods for the detection of chloroacetate esterase, peroxidase, and pseudoperoxidase, and by staining techniques for mast cells and eosinophils. Tissue was also examined using the indirect immunoperoxidase method for the presence of hemoglobin A (HbA) and F (HbF), for lysozyme (muramidase) and immunoglobins alpha, mu, gamma, kappa, lambda. Positive staining to some degree was seen in cells in the connective tissue stroma using all methods, and the cells stained corresponded to one or another of the types of pyroninophilic cells present. The finding of large cells with positive chloroacetate esterase and antilysozyme indicates the presence of granulopoiesis. Similarly, the presence of large nucleated cells with pseudoperoxidase and anti-hemoglobin (A and F) staining indicates the presence of erythropoiesis. Plasma cells were present in small numbers.
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PMID:Evidence for significant hematopoiesis in the human thymus. 5 99

The aromatic regions in proton-decoupled natural abundance 13C Fourier transform nuclear magnetic resonance spectra (at 14.2 kG) of small native proteins contain broad methine carbon bands and narrow nonprotonated carbon resonances. Some factors that affect the use of natural abundance 13C Fourier transform NMR spectroscopy for monitoring individual nonprotonated aromatic carbon sites of native proteins in solution are discussed. The effect of protein size is evaluated by comparing the 13C NMR spectra of horse heart ferrocytochrome c, hen egg white lysozyme, horse carbon monoxide myoglobin, and human adult carbon monoxide hemoglobin. Numerous single carbon resonances are observed in the aromatic regions of 13C NMR spectra of cytochrome c, lysozyme, and myoglobin. The much larger hemoglobin yields few resolved individual carbon resonances. Theoretical and some experimental values are presented for the natural linewidths (W), spin-lattice relaxation times (T1), and nuclear Overhauser enhancements (NOE) of nonprotonated aromatic carbons and Czeta of arginine residues. In general, the 13C-1H dipolar mechanism dominates the relaxation of these carbons. 13C-14N dipolar relaxation contributes significantly to 1/T1 of C epsilon2 of tryptophan residues and Czeta of arginine residues of proteins in D2O. The NOE of each nonprotonated aromatic carbon is within experimental error of the calculated value of about 1.2. As a result, integrated intensities can be used for making a carbon count. Theoretical results are presented for the effect of internal rotation on W, T1, and the NOE. A comparison with the experimental T1 and NOE values indicates that if there is internal rotation of aromatic amino acid side chains, it is not fast relative to the over-all rotational motion of the protein.
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PMID:Studies of individual carbon sites of proteins in solution by natural abundance carbon 13 nuclear magnetic resonance spectroscopy. Relaxation behavior. 16 39

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

An extracellular protein-polysaccharide-lipide (PPL) complex from exponentially growing cultures of Myxococcus virescens was purified by phosphate precipitation and gel chromatography. The high molecular weight slime polymer appeared homogenous upon isoelectric focusing. The PPL complex exhibited proteolytic activity against gelatin and the activity was only partly reduced by heat treatment. The function of the slime polymer as protein denatured was studied. The complex formed micelles similar to anionic detergents and it inhibited the precipitation and coagulation of proteins by trichloroacetic acid. Lysozyme was totally inactivated when treated with the PPL complex. By gel chromatography binding studies, the PPL complex was found to bind lysozyme in the ratio of 1 to 5.8 (w/w). After separation of added protein from the complex the anticoagulation effect on the protein remained. The biological function of the PPL complex was demonstrated with hemoglobin. When all susceptible peptide bonds in PPL-treated hemoglobin were hydrolyzed by trypsin only 20% in the urea-denatured protein were attacked. The combined role of slime and proteolytic activity is discussed.
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PMID:Myxobacterial slime and proteolytic activity. 41 87

Eleven male subjects took part in a 100 km running competition. Alterations in the total plasma protein and in ten individual plasma protein concentrations in blood and urine were measured prior to the run, immediately after and after 1 day of recovery. Five individual proteins showed a 7-10%, and lysozyme a 40%, increase in the plasma after the run. On the contrary, the haptoglobin concentration fell to 40% of its pre-race level. None of these variations were correlated with the plasma volume change. The present data showed a moderate hemolysis, as evidenced by plasma lysozyme and hemoglobin-haptoglobin binding. The urinary excretion of plasma proteins was slightly increased, especially albumin and alpha1-acid-glycoprotein. The renal clearance of plasma proteins revealed that the 100 km run induced a moderate increase of glomerular permeability without any signficant change in the tubular reabsorption process.
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PMID:Biochemical changes in a 100 km run: proteins in serum and urine. 42 76

Fats were fed either diets sufficient (300 ppm) or insufficient (5 ppm) in iron for 10 weeks. The iron-deficient animals had lowered hemoglobin and hematocrit levels and higher levels of kidney lysozyme activity than did control animals. There were no significant changes in serum and spleen lysozyme activity levels.
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PMID:Lysozyme levels in tissues of iron-deficient rats. 63 Dec 68

Two major proteins, termed proteins A and B, and one minor species, termed protein C, have been purified to homogeneity from dilute acid extracts of dormant spores of Bacillus megaterium. These three species comprise approximately 80% of the protein in the dilute acid extracts and account for 60 to 75% of the protein degraded during spore germination. All three proteins have low molecular weights (7,000 to 10,000), high isoelectric points (greater than 9.8), alanine as the NH2-terminal amino acid, are more hydrophilic than most proteins, and all lack cysteine, cystine, and tryptophan. In addition all three proteins are extremely sensitive to a wide variety of proteolytic enzymes, much more so than "average" proteins such as serum albumin, lysozyme, and hemoglobin. These proteins also bind to both purified DNA and to a nuclear body from dormant spores. Although this binding gives little or no protection to proteins A and B from proteolysis, it does result in elevation of the melting temperature of the DNA by as much as 20degrees.
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PMID:Purification and properties of some unique low molecular weight basic proteins degraded during germination of Bacillus megaterium spores. 80 43

Circular dichroism spectra have been obtained for albumin, alpha-chymotrypsinogen, collagen, concanavalin A, elastase, hemoglobin, histone f2b, alpha-lactalbumin, lactate dehydrogenase, beta-lactoglobulin, lysozyme, myoglobin, papain, ribonuclease A, and thermolysin in the presence of sodium dodecyl sulfate and dithiothreitol. While all spectra have the shape anticipated for a mixture of random coil and alpha helix, the intensities differ markedly ([theta]222 ranges from --1400 to --15 000 deg cm2/dmol). The variation in the circular dichroism can be quantitatively explained by a model which assumes that the arginyl, histidyl, and lysyl residues have an enhanced probability of propagating a helical segment in the presence of the detergent. The model also permits the computation of dimensional properties (unperturbed end-to-end distance and radius of gyration) for polypeptides of known amino acid sequence. Such computations have been performed for 67 proteins. The computed dimensions are compatible with experimental values and with the molecular weight dependence of the transport properties of the complexes. Furthermore, the model can account for the abnormal transport properties of the sodium dodecyl sulfate complexes formed by ribonuclease A, collagen fragments, and histones f2a1, f2a2, f2b, and f3. Even though some of the protein--sodium dodecyl sulfate complexes have helical contents as high as 50%, their overall conformation more closely approximates that of a random coil than a rod.
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PMID:Conformational properties of the complexes formed by proteins and sodium dodecyl sulfate. 96 36


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