The in situ gas-phase formation of a C-glycoside ion obtained during electrospray ionization tandem mass spectrometry. A unique intramolecular mechanism involving an ion-molecule reaction.

Rationale: This study examines the electrospray ionization mass spectrometry (ESI-MS), in-source collision-induced dissociation (CID) fragmentation and low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) of a synthetic pair of β- and α-anomers of the amphiphilic cholesteryl polyethoxy neoglycolipids containing the 2-azido-2-deoxy-D-galactosyl-D-GalN3 moiety. We describe the novel and unique in situ gas-phase formation of a C-glycoside ion formed during all these gas-phase processes and propose a reasonable mechanism for its formation.

Methods: The synthetic amphiphilic glycolipids were composed of the 2-deoxy-2-azido-D-galactosyl moiety (GalN3, the hydrophilic part) covalently attached to a polyethoxy spacer which is covalently linked to the cholesteryl moiety (hydrophobic part).

Evaluation of the analytical performance of the novel NS-Prime system and examination of temperature stability of fecal transferrin compared with fecal hemoglobin as biomarkers in a colon cancer screening program.

Objective: To examine the analytical aspects of fecal transferrin (Tf) and hemoglobin (Hb) measured on the NS-Prime analyzer for use in a colon cancer screening program.

Designs And Methods: Method evaluation and temperature stability studies for fecal Tf and Hb were completed. A method comparison was carried out against the NS-Plus system using samples collected from 254 screening program participants.

Direct targeted glycation of the free sulfhydryl group of cysteine residue (Cys-34) of BSA. Mapping of the glycation sites of the anti-tumor Thomsen-Friedenreich neoglycoconjugate vaccine prepared by Michael addition reaction.

We present in this manuscript the characterization of the exact glycation sites of the Thomsen-Friedenreich antigen-BSA vaccine (TF antigen:BSA) prepared using a Michael addition reaction between the saccharide antigen as an electrophilic acceptor and the nucleophilic thiol and L-Lysine ε-amino groups of BSA using different ligation conditions. Matrix laser desorption ionization time-of-flight mass spectrometry of the neoglycoconjugates prepared with TF antigen:protein ratios of 2:1 and 8:1, allowed to observe, respectively, the protonated molecules for each neoglycoconjugates: [M + H](+) at m/z 67,599 and 70,905. The measurements of these molecular weights allowed us to confirm exactly the carbohydrate:protein ratios of these two synthetic vaccines.

Characterizing changes in snow crab (Chionoecetes opilio) cryptocyanin protein during molting using matrix-assisted laser desorption/ionization mass spectrometry and tandem mass spectrometry.

Rationale: We report the matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) characterization of the cryptocyanin proteins of the juvenile Chionoecetes opilio crabs during their molting and non-molting phases. In order to assess the structural cryptocyanin protein differences between the molting and non-molting phases, the obtained peptides were sequenced by MALDI low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS).

Methods: The cryptocyanin protein was isolated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed by MALDI-TOF/TOF-MS.