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 correlation between protein solubility and the preferential interactions of proteins with solvent components was critically examined with aqueous MgCl2 as the solvent system. Preferential interaction and solubility measurements with three proteins, beta-lactoglobulin, bovine serum albumin, and lysozyme, resulted in similar patterns of interaction. At acid pH (pH 2-3) and lower salt concentrations (less than 2 M), the proteins were preferentially hydrated, while at higher salt concentrations, the interaction was either that of preferential salt binding or low salt exclusion. At pH 4.5-5, all three proteins exhibited either very low preferential hydration or preferential binding of MgCl2. These results were analyzed in terms of the balance between salt binding and salt exclusion attributed to the increase in the surface tension of water by salts, which is invariant with conditions. It was shown that the increase in salt binding at high salt concentration is a reflection of mass action, while its decrease at acid pH is due to the electrostatic repulsion between Mg2+ ions and the high net positive charge on the protein. The preferential interaction pattern was paralleled by the variation of protein solubility with solvent conditions. Calculation of the transfer free energies from water to the salt solutions for proteins in solution and in the precipitate showed dependencies on salt concentration. This indicates that the nature of interactions between proteins and solvent components is the same in solution and in the solid state, which implies no change in protein structure during precipitation. Analysis of the transfer free energies and preferential interaction parameter in terms of the salting-in, salting-out, and weak ion binding contributions has led to the conclusions that, when the weak ion binding contribution is small, the predominant protein-salt interaction must be that of preferential salt exclusion most probably caused by the increase of the surface tension of water by addition of the salt. A necessary consequence of this is salting-out of the protein, if the protein structure is to remain unaltered.
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PMID:Preferential interactions determine protein solubility in three-component solutions: the MgCl2 system. 233 71

The observed preferential hydration of proteins in aqueous MgCl2 solutions at low pH and low salt concentration (Arakawa et al., 1990) prompted a scrutiny of possible protein stabilization by MgCl2 under the same conditions, in view of earlier observations in aqueous solutions of sugars, amino acids, and a number of salts that preferential hydration is usually accompanied by the stabilization of the native structure of globular proteins. The results of thermal transition experiments on five proteins (ribonuclease A, lysozyme, beta-lactoglobulin, chymotrypsinogen, and bovine serum albumin) revealed neither significant stabilization nor destabilization of the protein structures by MgCl2 both at acid conditions (except for ribonuclease A, which was stabilized, but to a much smaller extent than by MgSO4) and at higher pH at which MgCl2 displayed little preferential hydration. This was in contrast to the great stabilizing action of MgSO4 at the same conditions. 2-Methyl-2,4-pentanediol (MPD), which gives a very large preferential hydration of native ribonuclease A at pH 5.8 [Pittz & Timasheff (1978) Biochemistry 17, 615-623], was found to be a strong destabilizer of that protein at the same conditions. Analysis of the preferentially hydrating solvent systems led to their classification into two categories: those in which the preferential hydration is independent of solution conditions and those in which it varies with conditions. The first always stabilize protein structure, while the second do not. In the first category the predominant interaction is that of cosolvent exclusion, determined by solvent properties, with the protein being essentially inert. In the second category interactions are determined to a major extent by the chemical nature of the protein surface.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Why preferential hydration does not always stabilize the native structure of globular proteins. 233 72

The 13C off-resonance rotating frame spin-lattice relaxation technique is applicable to the study of protein rotational diffusion behavior in both model in vitro and in vivo systems. The original formalism of James and co-workers [(1978) J. Am. Chem. Soc. 100, 3590-3594] was constrained by the assumption of random isotropic reorientational motion of a monodisperse protein population. Here we extend the formalism to include polydispersity. Application is made to the alkaline pH induced association of lysozyme, lysozyme-bovine serum albumin mixtures, and to the phase separation of lysozyme salt-water mixtures induced by low temperature.
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PMID:Assessment of protein reorientational diffusion in solution by 13C off-resonance rotating frame spin-lattice relaxation: effect of polydispersity. 233 12

Gel was prepared from 6-O-carboxymethyl-chitin (CM-chitin) by the addition of iron(III) chloride under mild conditions without any organic solvent. The optimal conditions for the gel formation were 15 to 30 mM iron(III) chloride and 0.5 to 0.8 degree of substitution in CM-chitin. The amounts of bovine serum albumin (BSA) and the anticancer drug doxorubicin (DOX) incorporated into CM-chitin gels were more than 80% and 30%, respectively under the conditions described above. The release of BSA or DOX from the gels was observed to be increased by lysozyme digestion in a time-dependent manner. This result indicates that CM-chitin might prove useful as a carrier gel for the sustained release of drugs and cytokines, including vaccines.
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PMID:6-O-carboxymethyl-chitin (CM-chitin) as a drug carrier. 233 66

Using 2 or 3 simple Good zwitterionic buffers at a 16 or 18 mmol/L final column concentration of the mixture, natural pH gradients of 4 to 8 and 3 to 9.5, respectively, were generated in a liquid LKB column. The pH gradients, stabilized by an anticonvective sucrose gradient, were linear, reproducible and stable in the electric field up to 5h. The pH gradients were used for isoelectric focusing of a number of impure proteins such as human hemoglobin, bovine serum albumin and chicken egg white lysozyme. The protein components could be well separated in the gradient, were easily recovered and appeared to be quite pure when analyzed by sodium dodecyl sulfate-gel electrophoresis. Furthermore, the pH gradient 4-8 was effectively used to isolate one of the acidic isozyme (pI 5.6) components of mouse liver alcohol dehydrogenase (EC 1.1.1.1) in an enzymatically active state, suggesting that the procedure does not denature proteins. The low cost, the ease with which the pH gradients are formed, their linearity, stability for a sufficient period to allow proteins to reach equilibrium and their subsequent recovery from buffer eluates should make the procedure interesting for electrofocusing of proteins.
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PMID:Column isoelectric focusing in natural pH gradients generated by biological buffers. 233 71

Reaction of beta-oligoglycosylamines obtained from carbohydrate chains of N-glycoproteins (ovalbumin, ovomucoid, riboflavin-binding glycoprotein from hen egg white, and asialofetuin) with bovine serum albumin, lysozyme, and poly(L-Asp) in presence of water-soluble carbodiimide gave rise to a series of glycoconjugates, modelling natural N-glycoproteins. Carbohydrate-peptide bond was shown to be of N-glycosylamide type with participation of Asp and Glu residues. The method allows one to obtain synthetic N-glycoproteins from oligomannoside, complex and hybrid oligosaccharide chains, and may find application both in biochemistry and biotechnology for improvement of physico-chemical properties of unglycosylated proteins.
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PMID:[Synthesis of N-glycoproteins with a native type of carbohydrate-peptide bond]. 234 12

Atraumatically collected nonstimulated (less than 1 microliter/min) and stimulated (greater than 50 microliters/min) tears from 30 clinically normal subjects were fractionated by size exclusion high-performance liquid chromatography (SE-HPLC). Enzyme-linked immunosorbent assay (ELISA) and kinetic assays were applied to relevant HPLC fractions to quantitatively identify 12 tear proteins. Secretory IgA levels were much higher in nonstimulated than in stimulated tears, and a similar disparity was seen also with IgA1 and IgA2 in the HPLC fraction containing secretory IgA. IgM levels were also higher in nonstimulated tears. Levels of the primary lacrimal gland proteins, lactoferrin, tear specific prealbumin, and lysozyme were similar in both types of tears. Significantly higher concentrations of the major serum proteins, IgG, transferrin, and serum albumin were measured in nonstimulated tears. Overall, 8 of the 12 proteins assayed were present at significantly higher concentrations in nonstimulated tears. These results show that tear flow rate strongly influences the protein profile obtained. Therefore, to allow valid comparisons of tear protein profiles within and between studies that use atraumatic collection procedures, an indication of flow rate during collection should be reported.
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PMID:Protein levels in nonstimulated and stimulated tears of normal human subjects. 235 14

A model system, consisting of bovine serum albumin, lysozyme and the cation exchanger S Sepharose FF, was used to investigate multicomponent protein adsorption to ion exchangers. Two models, one based on a complete absence of competition between adsorbing molecules and the other a competitive model, based on the assumption that all adsorption sites are available to both proteins, have been compared to experimental results. Evidence for competitive adsorption was seen in experiments in which breakthrough curves and the profiles of adsorbed proteins in packed beds were determined. However, although the results for packed-bed experiments were more closely predicted by the fully competitive model, some discrepancies were found suggesting that when considering multicomponent protein adsorption to ion exchangers it may also be necessary to take account of factors such as the molecular size of the adsorbing proteins and any potential inter-protein interactions, factors which may hinder the development of a general model of multicomponent protein adsorption to ion exchangers.
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PMID:Two-component protein adsorption to the cation exchanger S Sepharose FF. 235 64

Sweat samples were collected in a sauna from 74 healthy volunteers (72 men and 2 women) and concentrated. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of the individual samples revealed, in general, five main proteins and four PAS positive components. In pooled sweat, a method of SDS-PAGE followed by immunoblotting with specific antisera or antibodies against 24 human serum components was applied, and three out of the five main proteins showed the same molecular weights and antigenicities corresponding to serum albumin (67,000 Da), Zn-alpha 2-glycoprotein (42,000 Da) and lysozyme (14,000 Da). Moreover, orosomucoid, transferrin, IgG and IgA were demonstrated in the pooled sweat. Although alpha 1-antitrypsin was probably in the pooled sweat, other serum components could not be detected. On the pooled and individual sweat samples, anti-carcinoembryonic antigen (CEA) formed three bands at 42,000, 19,000 and 18,000 Da, but the antibody did not react with normal serum. It might be considered from these molecular weights that those sweat components are CEA-related antigens.
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PMID:Sweat protein components tested by SDS-polyacrylamide gel electrophoresis followed by immunoblotting. 239 53

The ferret trachea was mounted in an organ bath containing Krebs-Henseleit solution with additional bovine serum albumin (BSA). Tracheal secretions were collected and analyzed for albumin, and lysozyme, a specific marker of serous cell secretion. The total secretion volume and output and concentrations of albumin and lysozyme were calculated. Secretion was stimulated with methacholine (20 microM) (Mch), and the effects of the prostaglandins PGD2, PGE1, and PGF2 alpha on methacholine-induced secretion were studied. All responses were dose dependent. PGF2 alpha at 10(-5) M increased the volume of Mch-stimulated secretion twofold, the lysozyme output sixfold, and concentration over threefold, while decreasing the albumin transport by one-half. PGD2 at 10(-5) M reduced Mch-induced secretion volume to 75% control, increased albumin transport to 135%, without affecting lysozyme secretion. PGE1 at 10(-5) M increased Mch-stimulated albumin transport and concentration over twofold, decreased lysozyme release to less than one-third of control, and had no effect on secretion volume. PGE1 caused the albumin concentration to exceed that of the outer bath, indicating active transport. We conclude that prostaglandins selectively alter tracheal secretion induced by cholinergic stimuli.
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PMID:Prostaglandins alter methacholine-induced secretion in ferret in vitro trachea. 240 40


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