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)

Exposure to oil mist has been associated with a variety of acute and chronic respiratory effects. Using proteomics approaches to investigate exposure-associated proteins may provide useful information to understand the mechanisms of associated respiratory effects. The aim of this study was to investigate changes in rat bronchoalveolar lavage fluid proteins associated with oil mist exposure using nano-HPLC-ESI-MS/MS. The results revealed that 29 proteins exhibited significant changes after exposure. These proteins included surfactant-associated proteins (SP-A and SP-D), inflammatory proteins (complement component 3, immunoglobulins, lysozyme, etc.), growth factors (e.g., transforming growth factor alpha (TGF-alpha)), calcium-binding proteins (calcyclin, calgranulin A, calreticulin, and calvasculin), and other proteins (e.g., cathepsin D, saposin, and intestinal trefoil factor). To further evaluate changes in protein levels, a simple quantitative strategy was developed in this study. A large decrease in protein levels of SP-A and SP-D (0.24- and 0.38-fold, respectively) following exposure was observed. In contrast, protein levels of TGF-alpha and calcium-binding proteins were significantly increased (4.46- and 1.4-1.8-fold, respectively). Due to the diverse functions of these proteins, the results might contribute to understand the mechanisms involved in lung disorders induced by oil mist exposure.
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PMID:Proteomics analysis revealed changes in rat bronchoalveolar lavage fluid proteins associated with oil mist exposure. 1651 68

A desorption electrospray ionization (DESI) source has been coupled to an ion mobility time-of-flight mass spectrometer for the analysis of proteins. Analysis of solid-phase horse heart cytochrome c and chicken egg white lysozyme proteins with different DESI solvents and conditions shows similar mass spectra and charge state distributions to those formed when using electrospray to analyze these proteins in solution. The ion mobility data show evidence for compact ion structures [when the surface is exposed to a spray that favors retention of "nativelike" structures (50:50 water:methanol)] or elongated structures [when the surface is exposed to a spray that favors "denatured" structures (49:49:2 water:methanol:acetic acid)]. The results suggest that the DESI experiment is somewhat gentler than ESI and under appropriate conditions, it is possible to preserve structural information throughout the DESI process. Mechanisms that are consistent with these results are discussed.
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PMID:Coupling desorption electrospray ionization with ion mobility/mass spectrometry for analysis of protein structure: evidence for desorption of folded and denatured States. 1652 47

The interactions of cisplatin and its analogues, transplatin, carboplatin and oxaliplatin, with hen egg white lysozyme were analysed through ESI mass spectrometry, and the resulting metallodrug-protein adducts identified; the X-ray crystal structure of the cisplatin lysozyme derivative, solved at 1.9 A resolution, reveals selective platination of imidazole Nepsilon of His15.
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PMID:ESI mass spectrometry and X-ray diffraction studies of adducts between anticancer platinum drugs and hen egg white lysozyme. 1718 Feb 31

Electrospray ionization mass spectrometry (ESI-MS) is a commonly used tool for characterizing conformational changes of proteins in solution. Different conformations can be distinguished on the basis of their ESI charge state distributions. ESI-MS studies carried out under semidenaturing conditions result in bi- or multimodal distributions that reflect the presence of coexisting conformers. This study explores whether the concentration ratios of these species in solution are reflected in the measured ion intensities. Experiments on two model proteins, lysozyme and myoglobin, reveal that non-native polypeptide chains tend to result in a much stronger signal response than natively folded species. The measured ion intensity ratios can differ from the actual concentration ratios by as much as 2 orders of magnitude. It is proposed that the higher ionization efficiency of unfolded proteins is due to their partially hydrophobic character, which results in a larger surface activity and facilitates protein transfer into ion-producing progeny droplets. Conversely, natively folded proteins have a lower affinity for the air/liquid interface, such that ionization of these conformers is suppressed. The extent of ion suppression is strongly dependent on the experimental conditions such as flow rate and protein concentration, which determine if ESI occurs in a charge deficient or a charge surplus regime. These aspects should be taken into account for the design of ESI-MS-based protein folding experiments and for studies that use ion intensity ratios for the determination of protein-ligand binding affinities.
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PMID:Signal response of coexisting protein conformers in electrospray mass spectrometry. 1728 64

Desorption electrospray ionization-mass spectrometry (DESI-MS) was evaluated for the detection of proteins ranging in molecular mass from 12 to 66 kDa. Proteins were uniformly deposited on a solid surface without pretreatment and analyzed with a DESI source coupled to a quadrupole ion trap mass spectrometer. DESI-MS parameters optimized for protein detection included solvent flow rate, temperature of heated capillary tube, incident and reflection angle, sheath gas pressure, and ESI voltage. Detection limits were obtained for all protein standards, and they were found to decrease with decreasing protein molecular mass: for cytochrome c (12.3 kDa) and lysozyme (14.3 kDa) a detection limit of 4 ng/mm2 was obtained; for apomyoglobin (16.9 kDa) 20 ng/mm2; for beta-lactoglobulin B (18.2 kDa) 50 ng/mm2; and for chymotrypsinogen A (25.6 kDa) 100 ng/mm2. The DESI-MS analysis of higher molecular mass proteins such as ovalbumin (44.4 kDa) and bovine serum albumin (66.4 kDa) yielded mass spectra of low signal-to-noise ratio, making their detection and molecular weight determination difficult. In this study, DESI-MS proved to be a rapid and robust method for accurate MW determination for proteins up to 17 kDa under ambient conditions. Finally, we demonstrated the DESI-MS detection of the bacteriophage MS2 capsid protein from crude samples with minimal sample preparation.
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PMID:Desorption electrospray ionization-mass spectrometry of proteins. 1739 89

Amyloid fibril depositions are associated with many neurodegenerative diseases as well as amyloidosis. The detailed molecular mechanism of fibrillation is still far from complete understanding. In our previous study of in vitro fibrillation of hen egg white lysozyme, an irreversible partially unfolded intermediate was characterized. A similarity of unfolding kinetics found for the secondary and tertiary structure of lysozyme using deep UV resonance Raman (DUVRR) and tryptophan fluorescence spectroscopy leads to a hypothesis that the unfolding might be a two-state transition. In this study, chemometric analysis, including abstract factor analysis (AFA), target factor analysis (TFA), evolving factor analysis (EFA), multivariate curve resolution-alternating least squares (ALS), and genetic algorithm, was employed to verify that only two principal components contribute to the DUVRR and fluorescence spectra of soluble fraction of lysozyme during the fibrillation process. However, a definite conclusion on the number of conformers cannot be made based solely on the above spectroscopic data although chemometric analysis suggested the existence of two principal components. Therefore, electrospray ionization mass spectrometry (ESI-MS) was also utilized to address the hypothesis. The protein ion charge state distribution (CSD) envelopes of the incubated lysozyme were well fitted with two principal components. Based on the above analysis, the partial unfolding of lysozyme during in vitro fibrillation was characterized quantitatively and proven to be a two-state transition. The combination of ESI-MS and Raman and fluorescence spectroscopies with advanced statistical analysis was demonstrated to be a powerful methodology for studying protein structural transformations.
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PMID:The first step of hen egg white lysozyme fibrillation, irreversible partial unfolding, is a two-state transition. 1740 Sep 24

A series of genistein's phosphates were synthesized through a simplified Atherton-Todd reaction and the structures of the phosphates were determined by electrospray ionization mass spectrometry (ESI-MS) and NMR. In case of monophosporyl derivatives, NMR spectra show that substitutions occur at the 7-position of genistein but not at its 4' and 5-position. Moreover, the non-covalent complexes of lysozyme with the four new genistein phosphates were detected by ESI-MS.
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PMID:[Phosphorylated modification of genistein and their interaction with lysozyme]. 1763 7

Affinity constants for the binding of a range of substrate and non-substrate oligosaccharides to hen egg white lysozyme were determined by direct observation of the protein.ligand complexes using electrospray ionisation mass spectrometry (ESI-MS) with a chip-based nano-ESI source. The values obtained for a series of beta-1,4-N-acetylglucosamine oligomers (NAGn) were found to be in good agreement with those determined by fluorescence measurement. Oligomers of alpha-1,4-glucose (Glcn), which are believed to bind to lysozyme non-specifically, exhibited a 10(6)- to 10(8)-fold lower affinity for the enzyme. Lysozyme.NAGn complexes displayed an increase in Ka from n=2 to n=4, but then reached a plateau. In contrast non-specific lysozyme.Glcn complexes showed no such trend. Determination of gas-phase complex stability was achieved by quantitative collision-induced dissociation (CID) and infrared multiphoton dissociation (IRMPD) measurements. The collision energy (Ec50) or laser power (IRMPD50) required to dissociate precursor ions to 50% of their original intensity was determined for lysozyme.NAGn and Glcn complexes using the [M+8H]8+ charge state. An excellent correlation between trends in Ka and gas-phase stability was seen for NAGn oligomers bound to lysozyme, whereas no such relationship was observed with the non-specific, weaker lysozyme.Glcn complexes. These results illustrate that ESI-MS can be used to quantify the interactions between lysozyme and oligosaccharides in both the solution and gas phase and that measurement of gas-phase complex stability by CID or IRMPD can provide information about specific solution binding events.
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PMID:Quantitative determination of lysozyme-ligand binding in the solution and gas phases by electrospray ionisation mass spectrometry. 1792 88

We used gel electrophoresis and mass spectrometry to investigate differences in protein expression in ovarian tissues from Babesia bovis-infected and uninfected southern cattle tick, Rhipicephalus (Boophilus) microplus. Soluble and membrane proteins were extracted from ovaries of adult female ticks, and analyzed by isoelectric focusing (IEF) and one-dimensional or two-dimensional (2-D) gel electrophoresis. Protein patterns were analyzed for differences in expression between infected and uninfected ticks. 2-D separation of proteins revealed a number of proteins that appeared to be up- or down-regulated in response to infection with Babesia, in particular membrane/membrane-associated proteins and proteins in a low molecular mass range between 6 and 36kDa. A selection of differentially expressed proteins was subjected to analysis by capillary-HPLC-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS). Among the ovarian proteins that were up-regulated in infected ticks were calreticulin, two myosin subunits, an endoplasmic reticulum protein, a peptidyl-prolyl cis-trans isomerase (PPIase), a cytochrome c oxidase subunit, a glutamine synthetase, and a family of Kunitz-type serine protease inhibitors. Among the down-regulated ovarian proteins were another PPIase, a hemoglobin subunit, and a lysozyme. This study is part of an ongoing effort to establish a proteome database that can be utilized to investigate specific proteins involved in successful pathogen transmission.
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PMID:Differential protein expression in ovaries of uninfected and Babesia-infected southern cattle ticks, Rhipicephalus (Boophilus) microplus. 1796 48

It was shown in previous work that the interaction of growth factors (GFs) with adenosine triphosphate (ATP) is essential for their neuroprotective effect. Here we investigated the nature of the association of human basic fibroblast growth factor (bFGF), nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF) with ATP. It was demonstrated that this interaction involves the formation of non-covalent ATP-GF complexes that are labile at low pH and that could be selectively purified and subjected to electrospray and MALDI-TOF mass spectrometry. The results obtained with these techniques indicated that the stability of the complexes is high. Main features of the procedure used here are: (1) reversed-phase purification of nucleotide-protein non-covalent complexes, (2) their detection with MALDI-TOF-MS using acid-free matrix, and/or (3) their measurement with ESI-MS using soft desolvation conditions. The methodology was successful in providing proof for the presence of various nucleotide-GF complexes. It was extended to other nucleotide-binding proteins (ribonuclease A) as well as proteins that do not exhibit nucleotide binding (lysozyme) as positive and negative control, respectively. Thus, the method demonstrated its general use for the investigation of a wide range of proteins interacting with nucleotides as long as their complexes are sufficiently stable to accommodate the experimental conditions.
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PMID:Detection of ATP-binding to growth factors. 1805 12


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