Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The addition of solutions of bovine myelin basic protein to suspensions of unilamellar vesicles prepared from whole myelin suspensions results in the rapid equilibrium association of the vesicles into dimers, followed by time-dependent aggregation reactions. Other cationic proteins also induce the dimerization of the vesicles and equilibrium constants for dimer formation are obtained for bovine myelin basic protein, lysozyme, polyhistidine and myelin basic protein from carp, which differs from the bovine protein in that it contains no methylarginine residues. The bovine protein is more efficient at inducing dimer formation than the carp protein by approximately 0.93 kcal/mole; the carp protein is approximately as effective as the other cationic proteins examined. Complete methylation of the bovine MBP by AdoMet:MBP methyltransferase increases the interaction between MBP and the membrane by approximately 0.13 kcal/mole, consistent with the suggestion that a large portion of the free energy difference between the carp and bovine proteins arises from favorable interactions involving the methylarginine residues.
 ...
PMID:Mechanism of the interaction between myelin basic protein and the myelin membrane; the role of arginine methylation. 244 Apr 26

[methyl-(14)C]Methionine and S-adenosyl[methyl-(14)C]methionine were incorporated into the methoxycarotenoids spheroidene and spheroidenone by Rhodopseudomonas spheroides. The incorporation was greatly enhanced in the presence of lysozyme. On degradation of labelled spheroidene by hydriodic acid, the (14)C label was recovered in methyl iodide. Degradation of spheroidenone by reduction and allylic dehydration and demethylation of the reduction product gave a mixture of unlabelled carotenoid hydrocarbons, including 3,4-didehydrolycopene and 3,4-didehydro-7',8'-dihydrolycopene. The label from [methyl-(14)C]methionine and S-adenosyl[methyl-(14)C]methionine was located specifically in the methoxy group of spheroidene and spheroidenone. The biosynthesis of methoxycarotenoids in Rps. spheroides involves methylation of the tertiary hydroxyl groups of intermediates with S-adenosylmethionine.
 ...
PMID:Carotenoid biosynthesis in Rhodopseudomonas spheroides. S-adenosylmethionine as the methylating agent in the biosynthesis of spheroidene and spheroidenone. 454 66

1. Cell-free extracts of Bacillus subtilis synthesize methionine from serine and homocysteine without added folate. The endogenous folate may be replaced by tetrahydropteroyltriglutamate or an extract of heated Escherichia coli for the overall C(1) transfer, but tetrahydropteroylmonoglutamate is relatively inactive. 2. Extracts of B. subtilis contain serine transhydroxymethylase and 5,10-methylenetetrahydrofolate reductase, which are non-specific with respect to the glutamate content of the folate substrates. Methyl transfer to homocysteine requires a polyglutamate folate as methyl donor. These properties are not affected by growth of the organism with added vitamin B(12). 3. The synthesis of methionine from 5-methyltetrahydropteroyltriglutamate and homocysteine has the characteristics of the cobalamin-independent reaction of E. coli. No evidence for a cobalamin-dependent transmethylation was obtained. 4. S-Adenosylmethionine was not a significant precursor of the methyl group of methionine with cell-free extracts, neither was S-adenosylmethionine generated by methylation of S-adenosylhomocysteine by 5-methyltetrahydrofolate. 5. A procedure for the isolation and analysis of folic acid derivatives from natural sources is described. 6. The folates isolated from lysozyme extracts of B. subtilis are sensitive to folic acid conjugase. One has been identified as 5-formyltetrahydropteroyltriglutamate; the other is possibly a diglutamate folate. 7. A sequence is proposed for methionine biosynthesis in B. subtilis in which methyl groups are generated from serine and transferred to homocysteine by means of a cobalamin-independent pathway mediated by conjugated folate coenzymes.
 ...
PMID:Folic acid and the methylation of homocysteine by Bacillus subtilis. 462 1

The T3 phage enzymes S-adenosyl methionine cleaving enzyme and lysozyme and the T7 lysozyme were synthesized in a deoxyribonucleic acid (DNA)-dependent, cell-free system derived from uninfected Escherichia coli. The data presented suggest that these enzymes are encoded in that portion of the DNA which is transcribed early after infection.
 ...
PMID:T3 and T7 bacteriophage deoxyribonucleic acid-directed enzyme synthesis in vitro. 492 27

Polyamine levels were evaluated in human HL-60 promyelocytic leukemia cells after treatment with inducers of terminal differentiation. Differentiation in these cells was determined by increases in the percentage of morphologically mature cells and in lysozyme activity. Treatment of the HL-60 cells with phorbol 12-myristate-13-acetate (PMA), phorbol 12,13-didecanoate or other inducers of terminal differentiation such as dimethylsulfoxide and retinoic acid resulted in increased levels of putrescine. However, no increase in putrescine could be detected after PMA treatment of a HL-60 cell variant that exhibited a decreased susceptibility to PMA-induced terminal differentiation. Similarly, no increase in putrescine was observed with two non-tumor-promoters (phorbol 12,13-diacetate and 4-O-methyl-PMA) or with anthralin, a non-phorbol tumor promoter. In addition to enhancing putrescine levels, PMA also increased the amount of spermidine and decreased the amount of spermine. The increase in putrescine and spermidine preceded the expression of the various differentiation markers. Unlike the changes observed in the polyamine levels after PMA treatment, the activities of ornithine and S-adenosylmethionine decarboxylases, which are polyamine biosynthetic enzymes, did not significantly change. alpha-Methylornithine and alpha-difluoromethylornithine and methylglyoxal bis(guanylhydrazone), which are inhibitors of the polyamine biosynthetic enzymes, did not affect differentiation in control or PMA-treated cells. Because of these observations, we suggest that the change in polyamine levels involve biochemical pathways other than the known biosynthetic ones. By-products of these pathways may perhaps be the controlling factors involved in the induction of terminal differentiation in the HL-60 and other cell types as well.
 ...
PMID:Alterations in polyamine levels induced by phorbol diesters and other agents that promote differentiation in human promyelocytic leukemia cells. 694 Jan 23

Molecular simulations were performed to study the interactions between a protein (lysozyme, LYZ) and phosphorylcholine-terminated self-assembled monolayers (PC-SAMs) in the presence of explicit water molecules and ions. The results show that the water molecules above the PC-SAM surface create a strong repulsive force on the protein as it approaches the surface. The structural and dynamic properties of the water molecules above the PC-SAM surface were analyzed to provide information regarding the role of hydration in surface resistance to protein adsorption. It can be seen from residence time dynamics that the water molecules immediately above the PC-SAM surface are significantly slowed down as compared to bulk water, suggesting that the PC-SAM surface generates a tightly bound, structured water layer around its head groups. Moreover, the orientational distribution and reorientational dynamics of the interfacial water molecules near the PC-SAM surface were found to have the ionic solvation nature of the PC head groups. These properties were also compared to those obtained previously for an oligo(ethylene glycol) (OEG) SAM system and bulk water.
 ...
PMID:Molecular simulation studies of protein interactions with zwitterionic phosphorylcholine self-assembled monolayers in the presence of water. 1869 Jul 32

Molecular simulations were performed to investigate the origin of the strong repulsive force acting on a protein as the protein approaches an oligo (ethylene glycol) self-assembled monolayer (OEG-SAM) surface. Since the repulsive force is mainly generated from water molecules, the force from the water molecules near the surface was calculated layer by layer to further identify the molecular origin of the repulsive force. Results show that the strong repulsive force acting on the protein near the OEG-SAM surface is dominantly generated by the interfacial water molecules located between the OEG-SAM surface and lysozyme. A hydroxyl-terminated SAM (OH-SAM) surface was used for comparison. No significant repulsive force was observed from the water molecules between the protein and OH-SAM surface. Further studies show that the dipole distribution of the interfacial water molecules is significantly affected by the OEG-SAM surface, as opposed to the negligible impact from the OH-SAM surface. The interfacial water molecules above the OEG-SAM surface stay longer and reorient more slowly than those above the OH-SAM surface. These results from this work support the hypothesis that the OEG-SAM surface interacts strongly with interfacial water molecules and creates a stable hydration layer that prevents proteins from adsorbing to the surface.
 ...
PMID:Origin of repulsive force and structure/dynamics of interfacial water in OEG-protein interactions: a molecular simulation study. 1895 88

Yeast is widely used to determine the tertiary structure of eukaryotic proteins, because of its ability to undergo post-translational modifications such as glycosylation. A mutant lacking S-adenosylmethionine synthesis has been reported as a suitable host for producing selenomethionine derivatives, which can help solve phase problems in protein crystallography. However, the mutant required external addition of S-adenosylmethionine for cell proliferation. Here, a selenomethionine-resistant Pichia pastoris mutant that showed S-adenosylmethionine autotrophy was isolated. Human lysozyme expressed by the mutant under the control of constitutive promoter contained selenomethionine at 65% occupancy, sufficient for use as a selenomethionine derivative for single-wavelength anomalous dispersion phasing.
 ...
PMID:Use of novel selenomethionine-resistant yeast to produce selenomethionyl protein suitable for structural analysis. 1918 86

The stability of tethered globular proteins under denaturing conditions was interrogated with a hydrophobic surface, since conventional structural methods like circular dichroism (CD) and fluorescence or infrared spectroscopy could not be used because of the presence of an opaque solid substrate and extremely low surface concentrations. For free protein in solution, CD spectra gave well-known unfolding denaturing curves for lysozyme (LYS) and ribonuclease A (RNase A). The unfolding process for covalently tethered LYS and RNase A was followed, with multimolecular force spectroscopy (using an atomic force microscope in force-mode), via the adhesion energy between a functionalized self-assembled monolayer (CH(3)-SAM) probe and the protein molecules covalently bound to a carboxylic SAM on a gold-coated glass coverslip. The adhesion energy passed through a maximum for the tethered proteins during excursions with temperature or chemical denaturants. The initial rise in adhesion energy on increasing the temperature or GuHCl concentration was due to increasing exposure of the unfolded hydrophobic core of the proteins to the CH(3)-SAM tip, while the decrease in adhesion energy at high temperature or large concentrations of denaturant is attributed to interprotein association with nearest neighbors. Attempts to recover their folded state upon cooling (or reducing GuHCl concentration) were unsuccessful. Also, dilution of surface-tethered LYS reduced the aggregation with nearest neighbors about 6-fold. These results are in qualitative agreement with Monte Carlo simulations on a simple two-letter lattice protein model, especially for low concentrations of grafted proteins.
 ...
PMID:Stability of tethered proteins. 1933 22

Nonfouling surface coatings are of great interest for the development of advanced biomaterials used in biomedical and marine applications. Therefore, a lot of effort has been made to design new biocompatible materials and to understand the mechanisms of the protein repulsion. This study examines a series of polyglycerol (PG) dendrons modified by alkanethiols for their interactions with biofouling relevant proteins: fibrinogen (Fib), lysozyme (Lys), albumin (Alb), and pepsin (Pep). All polyglycerol dendrons [G1.0]-[G3.0] self-assembled monolayers with different terminal functionality (-OH, -OCH(3)) were prepared by applying simple Williamson ether formation followed by radical thiol addition to the alkene. Surface modification was performed by chemisorption of the different dendritic PG derivatives onto gold chips from ethanolic solution and then directly used in a screening with the respective proteins applying SPR spectroscopy. The effective and time-dependent SAM formation on gold was also revealed by X-ray photoelectron spectroscopy. It was demonstrated that the all polyglycerol dendrons [G1.0]-[G3.0] possess excellent resistance to the test proteins. Surprisingly, the SAMs of easily accessible [G1.0] dendron (M(w) = 426 g/mol) modified alkanethiol show the same high protein resistance as we could achieved for high molecular weight polymers (e.g., hyperbranched PG with M(n) = 2500 g/mol). However, significant changes in the amount of adsorbed proteins within the studied time frame of 24 h was not observed. Therefore, these oligoglycerol dendrons are a good alternative for the commonly used poly(ethylene glycol) (PEG).
 ...
PMID:Synthesis and characterization of glycerol dendrons, self-assembled monolayers on gold: a detailed study of their protein resistance. 1935 Nov 58


1 2 Next >>