|Alteration of urinary metabolic profile in rats treated with methylmercury|
Pierre Ayotte, Dinesh Kumar, Pierre-Yves Tremblay, Xiaolei Jin, Sevini Shahbaz, Rekha Mehta, Hing Man Chan, and Oliver Fiehn
A metabolomic approach was used to detect changes in urinary metabolic profile of rats treated orally with methylmercury (MeHg), a ubiquitous fish contaminant with well known neurotoxic properties. An aliquot of urine was collected on day 14, extracted and the extract successively methoxymated and trimethylsilylated prior to analysis by GC/TOF-MS. Results indicate that several metabolic pathways were altered by MeHg treatment, including urea cycle, glutathione metabolism and amino acid degradati
|Minor change in the structure major change in the mass spectrum in the example of an N-toluene-pyrrolidine derivative|
MS2 and further MSn spectra of SAR cannot provide sufficient information for metabolite structure elucidation because the masses of fragments in MSn correspond only to separate moieties of SAR. Nevertheless almost the exact structure of a dehydrogenated compound - has a poor MS2 spectrum - could be determined by further fragmentation in an LTQ-Orbitrap instrument and using the MSn mass spectra of an impurity of SAR.
|Capture Compounds towards a targeted reduction of proteome complexity|
Erik Duelsner, Aysel Alici, Christian Jurinke, Hubert Koester
Capture Compound Mass Spectrometry (CCMS) enables the enrichment of proteins based on their functionality. CCMS is commercialized as kits for research applications and in collaborations with pharmaceutical companies. The focus is on investigating mechanisms of drug action and avoidance of toxic effects of small molecule drugs.
|A Novel Approach to Internal Standardization in LC/MS/MS Analysis; Sensitive LC/MS/MS Analysis of Gentamicin|
Bruce Babson, Noel Henderson and Nicholas Chestara
A novel approach to internal standardization in LC/MS/MS is demonstrated. Gentamicin, a multi-component aminoglycoside, is derivatized with propyl-d7 chloroformate making the internal standard. Gentamicin components in the samples are derivatized with non-labeled propyl chloroformate making them analogous to the internal standard. Additional benefits of the derivatization are increased hydrophobicity and excellent MS/MS fragmentation.
|A novel method for coupling capillary columns|
Wil van Egmond, Daniela Peroni,
Using a proprietary, low-melting, deactivated glass we have developed a novel instant Meltfit™ connection. Reliable connectors are made in-situ in less than a minute.
|Single stage reversed-phase liquid chromatography-mass spectrometry for the characterization of triglyceride positional isomers.|
Haslina Hasan, Brendan J Keely and Julie Wilson
The high level of selectivity afforded by RP-HPLC in combination with CID allowed recognition of eight groups of TAG positional isomers. Development of UPLC approach has reduced the run time by half while maintaining separation. The improved method combined with principal components analysis was used to assess the extent of variation of major TAGs in subcutaneous and intermuscular pork fat from four different locations of adipose tissues.
|Five noncovalent peptidic ligands show different affinity rankings in solution and gas phase|
Andrey Dyachenko , Michael Goldflam , Marta Vilaseca , Ernest Giralt
Stability of noncovalent complexes of VEGF protein with 5 peptidic ligands is studied. Experiments were conducted in solution (NMR CSP, ITC) and in gas phase (CID TOF MS). Each ligand differs from others in chirality of one amino acid. It was shown, that trend of stability of the studied noncovalent complexes is reversed in the gas phase relatively to the solution. An explanation of this behavior is presented.
|Mass-Spectrometric Analysis with Sequenom EpiTYPER of GNAS Methylation in Pseudohypoparathyroydism Type Ib Patients Reveals Overall Methylation Defects also for the Familial Cases|
Benedetta Izzi1, Bart Claes2, Diether Lambrechts2, Chris Van Geet1,3, Kathleen Freson1
Sequenom EpiTYPER analysis of GNAS methylation in Pseudohypoparathyroidism type Ib patients reveals overall GNAS methylation defects also for the familial cases. Such abnormalities are not detectable via old methodologies such as PCR followed by methylation specific restriction digestion and are here for the first time described.
|Force Spectroscopy of the Iron Atom in Heme Proteins|
J. T. Sage, B M. Leu, T. H. Ching, Y. Zhang, J. E. Straub, J. Zhao, W. Sturhahn, E. E. Alp
Nuclear resonance vibrational spectroscopy (NRVS) selectively reveals the complete vibrational density of states (VDOS) of a Mössbauer probe nucleus within a protein. Frequency moments of the VDOS determine effective force constants for 57Fe at the active sites of cytochrome c (cyt c) and deoxymyoglobin (Mb).