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)

We report here a comprehensive infrared spectroscopic study of the interactions between the anesthetic nitrous oxide (N2O) and six proteins: lysozyme, cytochrome c, myoglobin, hemoglobin, serum albumin, and cytochrome c oxidase. Sites occupied by N2O molecules within these proteins were characterized. Three types of hydrophobic sites were found within the proteins. One with nu 3 near 2225 cm-1 is likely to be near peptide bond carbonyls; one with nu 3 near 2219 cm-1 may be near a benzene-like structure such as the side chains of phenylalanine and tyrosine; and the other with nu 3 near 2215 cm-1 is likely to be in a nonpolar alkane-like environment provided by the side chains of Leu, Ile, and Val residues. The amount of N2O molecules bound to myoglobin increases as the pH decreases from 9.2 to 5.2. N2O-protein interactions produced no detectable changes in the ligand-binding pockets of myoglobin, hemoglobin, and cytochrome c oxidase. N2O-induced secondary structure changes were detected only in the fully reduced cytochrome c oxidase, not in the fully oxidized oxidase and the other five proteins. N2O-induced conformational changes in the alpha beta-interface of hemoglobin and the h2 and h3 alpha-helices of human serum albumin were detected by monitoring the S-H stretch vibrations of cysteine residues. These findings provide direct evidence that anesthetic N2O interacts with proteins and occupies sites in the interior of the proteins.
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PMID:Characterization of sites occupied by the anesthetic nitrous oxide within proteins by infrared spectroscopy. 792 38

The human leukemic cell line LAMA-84 was established and characterized as an erythromegakaryocytic cell line. In the present study we show that these cells can differentiate in estrone-treated athymic mice and give rise to an erythroeosinophilic cell line (LAMA-87). This new cell line expressed glycoporin A, alpha beta and gamma globin chain mRNA but also eosinophilic peroxidase. Hemin slightly increased the total hemoglobin production of the cells and phorbol diester (TPA), dimethyl sulfoxide (DMSO) and sodium butyrate (SB) increased the expression of megakaryocytic markers (gpIIb/IIIa complex). When inoculated into non-treated athymic mice, LAMA-87 cells can differentiate to give rise to eosinomonocytic cells (LAMA-88). This new cell line expresses eosinophilic peroxidase, Luxol fast blue stain and synthesizes lysozyme. Depending on the inducer used, LAMA-88 can differentiate along a monocytic lineage (TPA, DMSO, SB and vitamin D3). These three LAMA cell lines should be useful in further studies of the molecular regulation of the pluripotent cell commitment and may provide a model for the understanding of human hematopoiesis.
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PMID:Selection and characterization of an erythroeosinophilic subclone (LAMA-87) and an eosinophilic subclone (LAMA-88) from the multipotential cell line LAMA-84. 799 72

Trichosanthin (TCS) is a ribosome-inactivating protein that has a wide range of biological and pharmacological activities. Due to its small molecular size, TCS is filtered by the glomerulus and can be recovered from urine. A previous experiment showed that the kidney is an important organ for its elimination. However, urine TCS recovery was unexpectedly small, suggesting renal reabsorption of this compound. To substantiate renal TCS reabsorption, different doses of TCS were injected intravenously into rats. Increasing the dose from 0.375 mg/kg to 12 mg/kg enhanced the percentage urine recovery from less than 0.29 +/- 0.06% to 39.07 +/- 2.46%. This demonstrated that TCS is reabsorbed by a saturable mechanism. Reabsorption of most small molecular weight filterable proteins shares a common endocytotic process. It is very likely that TCS utilizes the same process for reabsorption. When a filterable protein such as hemoglobin was infused with TCS, it competed with TCS for reabsorption and therefore increased the percentage urine TCS recovery to 35 +/- 2%. Infusion of another filterable protein, lysozyme, increased recovery to 3.2 +/- 0.8%. This supports the proposal that renal TCS uptake utilizes the common endocytotic mechanism. It was also found in this study that injection of TCS depressed the glomerular filtration rate (GFR), implying renal toxicity. This effect can be attributed to ribosome inactivation which takes place inside the cells. Should reabsorption of TCS be reduced, renal toxicity will disappear. For this purpose, dextran-trichosanthin (DXTCS) conjugate was synthesized to increase its effective molecular size.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Renal reabsorption of trichosanthin and the effect on GFR. 805 19

Differential scanning calorimetric (DSC) studies of the glassy states of as-received and hydrated lysozyme, hemoglobin, and myoglobin powders, with water contents of < or = 0.25, < or = 0.30, and < or = 0.29 g/g of protein, show that their heat capacity slowly increases with increasing temperature, without showing an abrupt increase characteristic of glass-->liquid transition. Annealing (also referred to as physical aging) of the hydrated proteins causes their DSC scans to show an endothermic region, similar to an overshoot, immediately above the annealing temperature. This annealing effect appears at all temperatures between approximately 150 and 300 K. The area under these peaks increases with increasing annealing time at a fixed temperature. The effects are attributed to the presence of a large number of local structures in which macromolecular segments diffuse at different time scales over a broad range. The lowest time scale corresponds to the > N-H and -O-H group motions which become kinetically unfrozen at approximately 150-170 K on heating at a rate of 30 K min-1 and which have a relaxation time of 5-10 s in this temperature range. The annealing effects confirm that the individual glass transition of the relaxing local regions is spread over a temperature range up to the denaturation temperature region of the proteins. The interpretation is supported by simulation of DSC scans in which the distribution of relaxation times is assumed to be exceptionally broad and in which annealing done at several temperatures over a wide range produces endothermic effects (or regions of DSC scans) qualitatively similar to those observed for the hydrated proteins.
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PMID:Calorimetric studies of the kinetic unfreezing of molecular motions in hydrated lysozyme, hemoglobin, and myoglobin. 813 Mar 42

FT-IR/PAS (Fourier transform infrared/photoacoustic spectroscopy) was used to evaluate the secondary structure of proteins. Four well-studied proteins, concanavalin A, hemoglobin, lysozyme, and trypsin, which have different distributions of secondary structures, were used for assignments of the infrared bands and evaluating the accuracy of FT-IR/PAS methods. Secondary structure contents estimated from FT-IR/PAS and other physical methods (e.g., X-ray diffraction, CD, and traditional FT-IR) show good agreement. In addition, the secondary structure can be evaluated with as little as 0.5 micrograms of protein (concanavalin A), suggesting that FT-IR/PAS is a sensitive and useful technique that could be applied to studies of the folding of recombinant and mutant proteins where only small amounts of material are available. Recombinant phosphorylase kinase gamma 1-300 subunit expressed in Escherichia coli was found in the inclusion bodies. We found that renatured phosphorylase kinase gamma 1-300 subunit has two kinase forms: one has a 10-fold higher activity than the other one. Both fractions, however, are the same as judged from sodium dodecylsulfate-polyacrylamide gel electrophoresis. Differences in conformation were demonstrated by using the FT-IR/PAS method, which showed that the low-activity form has more beta-sheet structure than the form with high activity. Analysis of these kinase forms by CD confirms the interpretation made by the FT-IR/PAS method.
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PMID:A study of protein secondary structure by Fourier transform infrared/photoacoustic spectroscopy and its application for recombinant proteins. 813 68

Eight patients with homozygous sickle cell anemia, 15 heterozygotes, and eight control individuals were investigated with respect to plasma concentrations of the inflammatory markers lysozyme and myeloperoxidase and the complement activation marker C3d. The patients showed significantly increased levels of myeloperoxidase and C3d, but not lysozyme, compared with the heterozygotes and the controls. The heterozygotes were also significantly different from the controls with regard to C3d concentration. The concentrations of myeloperoxidase and C3d in plasma showed a significant inverse correlation with the hemoglobin concentration. Myeloperoxidase and C3d showed a significant positive correlation. This suggests a role for the neutrophil and the complement system in the pathophysiology of sickle cell disease.
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PMID:Increased in vivo activation of neutrophils and complement in sickle cell disease. 827 46

The specificity of interactions between biological macromolecules and their ligands may be partially attributed to the directional properties of hydrogen bonds. We have now extended the GRID method (Goodford, P. J. J. Med. Chem. 1985, 28, 849. Boobbyer, D. N. A.; Goodford, P. J.; McWhinnie, P. M.; Wade, R. C. J. Med. Chem. 1989, 32, 1083), of determining energetically favorable ligand binding sites on molecules of known structure, in order to improve the treatment of groups which can make multiple hydrogen bonds. In this method, the interaction energy between a probe (a small chemical group that may be part of a larger ligand) and a target molecule is calculated using an energy function which includes a hydrogen bond term which is dependent on the length of the hydrogen bond, its orientation at the hydrogen-bonding atoms, and their chemical character. The methods described in the preceding paper (Wade, R. C.; Clark, K. J.; Goodford, P. J. J. Med. Chem., preceding paper in this issue) for probes capable of making two hydrogen bonds are here extended to the following probes which have the ability to make more than two hydrogen bonds: ammonium-NH3+, amine-NH2, sp3-hybridized hydroxyl, and water. Use of the improved GRID procedure is demonstrated by the determination of the conformation of an amino acid side chain at the subunit interface in hemoglobin and of the location of water binding sites in human lysozyme.
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PMID:Further development of hydrogen bond functions for use in determining energetically favorable binding sites on molecules of known structure. 2. Ligand probe groups with the ability to form more than two hydrogen bonds. 842 Dec 81

In erythrocytes suspended in isotonic medium, a number of fluorinated anions showed well resolved 19F NMR resonances from the solute populations in the intra- and extracellular compartments; the intracellular resonances were shifted to higher frequency (low field). In addition 19F NMR resonances of extracellular solutes were shifted to higher frequency when bovine serum albumin was incorporated into the extracellular medium. The dependence of 19F NMR chemical shift on protein concentration was also demonstrated using resealed red cell ghosts and liposomes; in the presence of external hemoglobin, lysozyme and bovine serum albumin, the shift of the external resonances was to higher frequency. In addition, significant high frequency shifts of 19F NMR resonances were evident along with an increase of temperature. The results of the present study further support the contention that the principal physical basis for the shifts is the disruption of direct hydrogen bonds between 19F of the solutes and (primarily) solvent H2O by protein hydration. The 'split peak' phenomenon is of general importance in biological systems where a transmembrane protein-concentration difference exists.
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PMID:Transmembrane 19F NMR chemical shift difference of fluorinated solutes in liposomes, erythrocytes and erythrocyte ghosts. 849 44

Renin can be detected in cardiovascular and other tissues but it disappears after bilateral nephrectomy indicating that tissues can take up or bind renal renin from the circulation. If renin uptake is the result of specific binding, plasma prorenin may be a natural antagonist of tissue directed renin-angiotensin systems. To investigate if specific prorenin/renin uptake occurs in rat tissues, binding studies were performed, with rat microsomal membrane preparations using recombinant rat prorenin metabolically labeled with 35S-methionine as a probe. A high affinity binding site for both renin and prorenin was identified. Affinities for prorenin and renin were approximately 200 and 900 pmol/L, respectively. Binding was reversible, saturable, and pH and temperature dependent. The relative binding capacities of membranes from various rat tissues were as follows (fmol/mg): renal cortex (55), liver (54), testis (63), lung (31), brain (18), renal medulla (15), adrenal (17), aorta (7), heart (4), and skeletal muscle (1). Bound prorenin was displaced by rat and human renin or prorenin but not by the prosequence of rat prorenin, angiotensin I or II, rat or human angiotensinogen, the renin inhibitor SQ30697, atrial natriuretic factor, amylase, insulin, bovine serum albumin, hemoglobin, heparin, lysozyme, ovalbumin, cytochrome C, pepsin, pepsinogen, ribonuclease A, mannose-6-phosphate, alpha-methyl mannoside, gonadotropin releasing hormone, or an antibody to hog renin binding protein. these results demonstrate specific binding of prorenin to a site in rat tissues, herein named ProBP, that also binds renin. It is possible that differences in prorenin/renin binding capacity determine the activity of tissue-directed renin-angiotensin systems and that prorenin is a natural antagonist. Alternatively, a prorenin/renin receptor may have been identified that may function by transducing an intracellular signal.
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PMID:Specific prorenin/renin binding (ProBP). Identification and characterization of a novel membrane site. 873 81

The epigastrium was irradiated by low-energy infrared Skalyar laser in intact noninbred rats. The energy exposure at 5 and 20 MW was found to be accompanied by the development of leukocytosis at the expense of all types of leukocytes, the extensiveness of early phases of polynuclear phagocytic activity, increases in neutrophilic redox processes and complement titers during 7 days of the experiment. The count of red blood cells, the levels of hemoglobin, and lysozyme enzymatic activity were decreased, hematocrit remained in the normal ranges. Increasing the exposure rate up to 40 MW retarded the responses of defensive mechanisms or resulted in their baseline suppression.
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PMID:[Status of the blood system and nonspecific anti-infection defense during external irradiation of rats with a low-energy infrared laser]. 908 16


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