Clustering of nucleosides in the presence of alkali metals: Biologically relevant quartets of guanosine, deoxyguanosine and uridine observed by ESI-MS/MS

2003 ◽  
Vol 38 (1) ◽  
pp. 87-97 ◽  
Author(s):  
Tenna Aggerholm ◽  
Sergio C. Nanita ◽  
Kim J. Koch ◽  
R. Graham Cooks
Keyword(s):  
Alkali Metals ◽  
Biologically Relevant ◽  
Esi Ms

β-Carboline directed regioselective hydroxylation by employing Cu(OAc)2 and mechanistic investigation by ESI-MS

2020 ◽  
Vol 18 (12) ◽  
pp. 2307-2311 ◽  
Author(s):  
Darshana Bora ◽  
Ramya Tokala ◽  
Stephy Elza John ◽  
Bitla Prasanth ◽  
Nagula Shankaraiah
Keyword(s):  
Biologically Relevant ◽  
Esi Ms ◽  
Mechanistic Investigation ◽  
Regioselective Hydroxylation ◽  
Biologically Relevant Molecules

This protocol demonstrates microwave-irradiated monohydroxylation on different heterocycles via C–H functionalization which leads into the development of biologically relevant molecules.

scholarly journals The Effect of Stereochemistry on Sodium Ion Complexation in Nucleoside-Metallacarborane Conjugates

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Agnieszka B. Olejniczak ◽  
Jan Milecki ◽  
Grzegorz Schroeder
Keyword(s):  
Complex Formation ◽  
Alkali Metals ◽  
Equilibrium Constants ◽  
Biological Properties ◽  
Biological Evaluation ◽  
Sodium Ion ◽  
Pyrimidine Nucleosides ◽  
Esi Ms ◽  
Complexing Properties ◽  
Physicochemical And Biological Properties

Conjugates of purine and pyrimidine nucleosides: thymidine and -deoxyguanosine with cobalt-metallacarborane were studied for their sodium ion complexing properties. Formation of stable complexes of 1 : 1 stoichiometry was proved by ESI MS spectroscopy and NMR. Equilibrium constants and energies of complex formation were calculated. Complexation of alkali-metals by nucleoside-metallacarborane conjugates may affect the physicochemical and biological properties of the conjugates and should be taken into consideration during biological evaluation of these types of modifications.

scholarly journals Electrospray Ionization Mass Spectrometry as a Valuable Tool in the Characterization of Novel Primaquine Peptidomimetic Derivatives

2009 ◽  
Vol 15 (5) ◽  
pp. 627-640 ◽  
Author(s):  
Nuno Vale ◽  
Joana Matos ◽  
Rui Moreira ◽  
Paula Gomes
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Ionization ◽  
Ion Trap ◽  
Chemical Characterization ◽  
Ionization Mass ◽  
Biologically Relevant ◽  
Esi Ms ◽  
Physico Chemical ◽  
Fragmentation Patterns

Novel primaquine-derived antimalarials have been extensively characterized by electrospray ionization-ion trap mass spectrometry (ESI-MS). Experiments by in-source collision-induced dissociation (CID) in the nozzle–skimmer region (NSR) or by tandem mass spectrometry (MS/MS) are shown to be most valuable tools for the physico–chemical characterization of these 8-aminoquinolinic drugs that also bear the biologically relevant imidazolidin-4-one scaffold. It was possible to find parallelism between compound stability in the NSR and its reactivity towards hydrolysis at physiological pH and T. Moreover, MS/MS fragmentation patterns were characteristic for each family, providing a means for structural distinction of isomers and allowing interesting correlations to be found between the relative abundance of particular fragments and relevant structure–activity determinants, such as the Charton steric parameter, ν. In conclusion, this work provides a solid ground for establishing ESI-MS as a key tool for the physico–chemical characterization of biopharmaceuticals bearing the 8-aminoquinoline and/or the imidazolidin-4-one moieties.

ESI MS studies highlight the selective interaction of Auranofin with protein free thiols

2020 ◽  
Vol 49 (18) ◽  
pp. 5906-5913 ◽  
Author(s):  
Carlotta Zoppi ◽  
Luigi Messori ◽  
Alessandro Pratesi
Keyword(s):  
Mode Of Action ◽  
Cysteine Residues ◽  
Biologically Relevant ◽  
Esi Ms ◽  
Selective Interaction

The study of the mode-of-action of Auranofin, a cytotoxic gold(i) compound, reveals that it binds exclusively to the free and solvent-accessible cysteine residues of biologically relevant proteins.

Investigation of thin sections of biological standards by EDX, EELS, and Auger electron spectroscopy

1990 ◽  
Vol 48 (2) ◽  
pp. 184-185
Author(s):  
S. Lehner ◽  
H.E. Bauer ◽  
R. Wurster ◽  
H. Seiler
Keyword(s):  
Processing System ◽  
Beam Current ◽  
Beam Diameter ◽  
Thin Sections ◽  
Biologically Relevant ◽  
Energy Filtering ◽  
Low Viscosity ◽  
Carbon Foils ◽  
Electron Microscopical ◽  
Exchange Membrane

In order to compare different microanalytical techniques commercially available cation exchange membrane SC-1 (Stantech Inc, Palo Alto), was loaded with biologically relevant elements as Na, Mg, K, and Ca, respectively, each to its highest possible concentration, given by the number concentration of exchangeable binding sites (4 % wt. for Ca). Washing in distilled water, dehydration through a graded series of ethanol, infiltration and embedding in Spurr’s low viscosity epoxy resin was followed by thin sectioning. The thin sections (thickness of about 50 nm) were prepared on carbon foils and mounted on electron microscopical finder grids.The samples were analyzed with electron microprobe JXA 50A with transmitted electron device, EDX system TN 5400, and on line operating image processing system SEM-IPS, energy filtering electron microscope CEM 902 with EELS/ESI and Auger spectrometer 545 Perkin Elmer.With EDX, a beam current of some 10-10 A and a beam diameter of about 10 nm, a minimum-detectable mass of 10-20 g Ca seems within reach.

Quantification of cell-surface expressed antigenic sites with 5-nm gold markers: Getting close to biologically relevant data

1989 ◽  
Vol 47 ◽  
pp. 1050-1051
Author(s):  
Etienne de Harven ◽  
Hilary Christensen ◽  
Richard Leung ◽  
Cameron Ackerley
Keyword(s):  
Cell Surface ◽  
Human Peripheral Blood ◽  
Contour Length ◽  
Thin Sections ◽  
Gold Particles ◽  
Biologically Relevant ◽  
Transmission Electron ◽  
Entire Cell ◽  
Electron Imaging ◽  
Cell Contour

The T-derived subset of human peripheral blood normal lymphocytes has been selected as a model system to study the usefulness of 5 nm gold markers for quantification of single epitopes expressed on cell surfaces. The chosen epitopes are parts of the CD3 and CD5 molecules and can be specifically identified by hybridoma produced monoclonal antibodies (MoAbs; LEU-4 and LEU-1; Becton-Dick- inson, Mountain view, CA) . An indirect immunolabeling procedure, with goat anti-murine IgG adsorbed on the surface of 5 nm colloidal gold particles (GAM-G5, Janssen Pharmaceutica, Beerse, Belgium) has been used. Backscattered Electron Imaging (BEI) in a field emission scanning electronmicroscope (SEM) and transmission electron microscopy of thin sections of lymphocytes labeled before plastic embedding, were both used to identify and quantitate gold labeled cell surface sites, Estimating that the thickness of “silver” sections is approximately 60 nm and counting the number of gold particles on the entire cell perimeter, we calculated that, for LEU-4, the number of markers per um2 of cell surface is in the 140-160 range (Fig.l). Cell contour length measurements indicated that the surface of one lymphocyte is approximately 130-160 um2 that of a smooth sphere of identical diameter, reflecting the role of microvilli in expanding the surface area. The total number of gold labeled sites on the surface of one lymphocyte averages, therefore between 20,000 and 24,000 per cell.

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