Home  About us  Contact
 

Mass Spectrometric Investigation (mass + spectrometric_investigation)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Electrospray mass spectrometric investigation of the binding of cis -parinaric acid to bovine beta-lactoglobulin and study of the ligand-binding site of the protein using limited proteolysis

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2003
Tímea Imre
The binding property of parinaric acid, a polyunsaturated fatty acid, to bovine , -lactoglobulin, has been studied by electrospray ionization mass spectrometry. Stable complexation was observed under acidic conditions in a molar ratio of 1:1. Competitive complexation experiments were performed using saturated and unsaturated fatty acid standards with different chain lengths and number of double bonds to study the specificity of the interaction. It can be concluded that formation of the parinaric acid,lactoglobulin complex is preferred even if the molar concentration of the other fatty acids is ten times higher. In cases of specific complex formation the protein must have an active site that is a good acceptor for the ligand molecule. Limited trypsinolysis was performed on the lactoglobulin molecule to identify which part is responsible for the complexation. An intermediate tryptic fragment with molecular mass of 5200,Da was found to have the same ability to bind parinaric acid as the intact protein. This disulfide-bonded residue, [41-70]S-S[149-162], might thus be involved in the specific complexation of parinaric acid to , -lactoglobulin. This conclusion is consistent with previous information on this binding site. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Reactivity of the NS2/3(907,1206)ASK4 protein with ,-mercaptoethanol studied by electrospray ion trap mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2002
Laura Orsatti
The present work reports a mass spectrometric investigation of the NS2/3 protein, a protease from hepatitis C virus (HCV). During routine protein manipulation, in the presence of 100,mM ,-mercaptoethanol and under denatured conditions, the protein was unexpectedly modified at its cysteine residues, and the increased molecular weight corresponded to one molecule of ,-mercaptoethanol bound. The modified protein, once refolded, was found to be less active than the unmodified one. The aim of this work was to investigate whether the reactivity of cysteines with ,-mercaptoethanol involves one specific, highly reactive residue of the sequence, or if the modification is a random process. Liquid chromatography (LC) coupled on-line with an electrospray ion trap mass spectrometer was used to identify the modification sites. It was found that five cysteines out of nine had reacted with ,-mercaptoethanol, none of them showing a significantly higher reactivity than the others. 95% of sequence coverage was obtained. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Investigation of Protein,Ligand Interactions by Mass Spectrometry

CHEMMEDCHEM, Issue 4 2007
Andrea Sinz Prof.
Abstract The rate of drug discovery is greatly dependent on the development and improvement of rapid and reliable analytical methods that allow screening for protein,ligand interactions. The solution-based methods for investigating protein,ligand interactions by mass spectrometry (MS), which are discussed in this paper, are hydrogen/deuterium exchange of protein backbone amide hydrogens, and photoaffinity labeling. Moreover, MS analysis of intact noncovalent protein,ligand complexes is described. Fourier transform ion cyclotron resonance mass spectrometry (FTICR,MS) with its ultra-high resolution and excellent mass accuracy is also considered herein as it is gaining increasing popularity for a mass spectrometric investigation of protein,ligand interactions. [source]

Study of bisphosphonates by matrix-assisted laser desorption/ionization mass spectrometry , influence of alkali atoms on fragmentation patterns

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2009
Erwann Guénin
1-Hydroxymethylene-1,1-bisphosphonic acids (or bisphosphonates) are compounds that have interesting pharmacological applications. However, few mass spectrometric investigations have been carried out to determine their fragmentation patterns. Herein, we evaluated different matrices for the study by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of the formation and fragmentation of the protonated, the cationized (MNa+ and MK+) and the deprotonated bisphosphonates. Some in-source fragmentations were observed both in positive and in negative ion modes. The fragmentation patterns obtained in post-source decay mode are also discussed. In contrast to previous electrospray ionization/multi-stage mass spectrometry (ESI-MSn) studies, some new fragmentation pathways were deduced and the effects of alkali ions on the fragmentation patterns were shown. The results summarized here completed the data previously recorded by ESI-MSn and could be used for the characterization of bisphosphonates as alkali complexes in biological mixtures. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Mechanistic investigation of the interaction between bisquaternary antimicrobial agents and phospholipids by liquid secondary ion mass spectrometry and differential scanning calorimetry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2002
V. A. Pashynskaya
Mechanisms of interaction between the antimicrobial drugs decamethoxinum and aethonium, which are based on bisquaternary ammonium compounds, and a phospholipid component of biological membranes, dipalmitoylphosphatidylcholine, were studied by means of liquid secondary ion mass spectrometry (LSIMS) and differential scanning calorimetry (DSC). Supramolecular complexes of the drugs with this phospholipid were recorded under secondary ion mass spectrometric conditions. The dependence of the structures of these complexes on structural parameters of the dications of the bisquaternary ammonium compounds was demonstrated. Tandem mass spectrometric investigations of the metastable decay of doubly charged ions of decamethoxinum and aethonium complexes with dipalmitoylphosphatidylcholine allowed estimation of structural parameters of these complexes in the gas phase. Interactions of decamethoxinum and aethonium with model membrane assemblies built from hydrated dipalmitoylphosphatidylcholine were studied using DSC. It was shown that while both drugs can interact with model membranes, the mechanisms of such interactions for decamethoxinum and aethonium differ. The correlation between the nature of these interactions and structural and electronic parameters of the dications of the two bisquaternary agents is discussed. Interpretation of combined mass spectrometric and calorimetric experimental data led to proposals that the molecular mechanisms of antimicrobial action of bisquaternary ammonium compounds are related to their effect on the membrane phospholipid components of microbial cells. Copyright © 2002 John Wiley & Sons, Ltd. [source]