Search results for "solution"
showing 10 items of 5638 documents
Template-Directed Protein Folding into a Metastable State of Increased Activity
1995
The principal objective of this work was to distinguish between kinetic and thermodynamic reaction control in protein folding. The deleterious effects of a specific mutation on spontaneous refolding competence were analyzed for this purpose. A Bowman-Birk-type proteinase inhibitor of trypsin and chymotrypsin was selected as a double-headed model protein to facilitate the detection of functional irregularities by the use of functional assays. The parent protein spontaneously folds into a single, fully active and thermodynamically stable state in a redox buffer after reduction/denaturation. By contrast, the properties of a P'1Ser--Pro variant in the trypsin-reactive subdomain differ before an…
Protein Biomarkers of Bovine Defective Meats at a Glance: Gel-Free Hybrid Quadrupole-Orbitrap Analysis for Rapid Screening
2021
An understanding of biological mechanisms that could be involved in the stress response of animal cattle prior to slaughter is critical to create effective strategies aiming at the production of high-quality meat. The sarcoplasmic proteome of directly extracted samples from normal and high ultimate pH (pHu) meat groups was studied through a straightforward gel-free strategy supported by liquid chromatography hybrid quadrupole-Orbitrap high-resolution mass spectrometry (LC-HRMS) analysis. A stepped proteomic pipeline combining rapid biomarker hunting supported by qualitative protein Mascot scores followed by targeted label-free peptide quantification revealed 26 descriptors that characterize…
Identification of Rothia Bacteria as Gluten-Degrading Natural Colonizers of the Upper Gastro-Intestinal Tract
2011
Background Gluten proteins, prominent constituents of barley, wheat and rye, cause celiac disease in genetically predisposed subjects. Gluten is notoriously difficult to digest by mammalian proteolytic enzymes and the protease-resistant domains contain multiple immunogenic epitopes. The aim of this study was to identify novel sources of gluten-digesting microbial enzymes from the upper gastro-intestinal tract with the potential to neutralize gluten epitopes. Methodology/Principal Findings Oral microorganisms with gluten-degrading capacity were obtained by a selective plating strategy using gluten agar. Microbial speciations were carried out by 16S rDNA gene sequencing. Enzyme activities wer…
"Design and application of a data-independent precursor and product ion repository."
2012
The functional design and application of a data-independent LC-MS precursor and product ion repository for protein identification, quantification, and validation is conceptually described. The ion repository was constructed from the sequence search results of a broad range of discovery experiments investigating various tissue types of two closely related mammalian species. The relative high degree of similarity in protein complement, ion detection, and peptide and protein identification allows for the analysis of normalized precursor and product ion intensity values, as well as standardized retention times, creating a multidimensional/orthogonal queryable, qualitative, and quantitative spac…
Natural or synthetic nucleic acids encapsulated in a closed cavity of amphiphiles
2013
In this review some aspects of the interactions of organized structures of amphiphiles with natural or synthetic DNAs are briefly considered. In particular DNAs encapsulated in closed cavities of amphiphiles, specifically giant vesicles and water-in-oil droplets and reverse micelles, are dealt with. Two main applications of giant vesicles are reviewed in detail, namely their use as microreactors where reactions can be followed by optical microscopy on a single vesicle and in synthetic biology as protocell models or as potential semi-synthetic ‘‘living’’ cells. Water-in-oil droplets uses for rapid and relatively low-cost DNA amplification by PCR reaction are described as well as for in vitro…
Thermodynamics of Proton Binding of Halloysite Nanotubes
2016
In this paper, new information on physical and chemical properties of the widely used nanostructured Halloysite mineral are reported. Given that the Halloysite has a tubular structure formed by a variable number of wrapped layers containing Si-OH and Al-OH groups, their proton binding affinity was measured at different ionic strengths and ionic media by means of potentiometric measurements in heterogeneous phase. One protonation constant for the Si-OH groups and two for the Al-OH groups were determined. The protonation constant values increase with increasing of the ionic strength in all the ionic media. This suggests that the presence of a background electrolyte stabilizes the protonated s…
Bohr-effect and buffering capacity of hemocyanin from the tarantula E. californicum.
2003
A previous report showed that binding of oxygen to the 24-meric hemocyanin from E. californicum does not correlate linearly with the release of protons as known from hemoglobin. However, this unusual complex phenomenological observation could not be explained at that time. Here, I present a full analysis of the thermodynamic coupling between protons and oxygen for the 24-meric tarantula hemocyanin in Ringer-solution based on the Nested-MWC-model. A strategy is presented which allows to reduce the number of free parameters when fitting the model to the data by including explicitly the equilibrium constants for binding of protons to the different conformations. The results show that the Neste…
Patterning of Magnetic Bimetallic Coordination Nanoparticles of Prussian Blue Derivatives by the Langmuir–Blodgett Technique
2012
We report a novel method to prepare patterns of nanoparticles over large areas of the substrate. This method is based on the adsorption of the negatively charged nanoparticles dispersed in an aqueous subphase onto a monolayer of the phospholipid dipalmitoyl-l-α-phosphatidylcholine (DPPC) at the air-water interface. It has been used to prepare patterns of nanoparticles of Prussian blue analogues (PBA) of different size (K(0.25)Ni[Fe(CN)(6)](0.75) (NiFe), K(0.25)Ni[Cr(CN)(6)](0.75) (NiCr), K(0.25)Ni[Co(CN)(6)](0.75) (NiCo), Cs(0.4)Co[Cr(CN)(6)](0.8) (CsCoCr), and Cs(0.4)Co[Fe(CN)(6)](0.9) (CsCoFe)). The behavior of DPPC monolayer at the air-water interface in the presence of the subphase of P…
EIS and Ac-electrogravimetry study of PB films in KCl, NaCl, and CsCl aqueous solutions
2003
Prussian Blue films have been studied by means of ac-electrogravimetry, electrochemical impedance spectroscopy, and electrochemical quartz crystal microbalance in different aqueous salt solutions. Impedance data was interpreted in terms of a model based on a potential drop at the electrode/film interface and a potential drop at the film/solution interface. Quantitative results obtained by the fitting of impedance and ac-electrogravimetry allow to conclude that the main contribution to the potential drop at the film/solution interface is due to the dehydration-hydration process of cations on entering or leaving the film.
Stability of Prussian Blue films on ITO electrodes: effect of different anions
1993
Abstract Transformation of insoluble newly deposited Prussian Blue (PB) into the soluble structure stabilizes the film and allows its total oxidation to Prussian Yellow. The stability of PB films in electrochemical processes in successive potential cycling experiments and under long-term chemical attack by an electrolyte depends not only on the cation that takes part but also on the nature of the anion present. In aqueous media, the sulphate ion clearly destabilizes the crystalline structure whereas the nitrate ion favours stabilization. Initial changes in the voltammograms recorded immediately after the spectroscopic tests have been detected in all media. During the immersion period water …