1994/04/01 by Rachel R. Ogorzalek Loo, Richard D. Smith, Richard Smith
Chemistry · Engineering · #Analytical Chemistry (journal) #Analytical Chemistry and Chromatography #Biomolecule #Chemistry #Chromatography #Cysteine #Diethylamine #Electrospray #Electrospray ionization #Inorganic chemistry #Mass Spectrometry Techniques and Applications #Mass spectrometry #Microfluidic and Capillary Electrophoresis Applications #Molecule #Organic chemistry
paper · doi:10.1016/1044-0305(94)85011-9
openalex publication_date 1994/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Proton transfer reactions of ammonia, dimemylamine, diethylamine, and trimethylarnine with multiply protonated proteins generated by electrospray ionization (ESI) were examined to probe the relationship between solution and gas-phase protein structure and the relationship with ion-molecule reactivity. The ion-molecule reactions were carried out in an atmospheric pressure capillary inlet/reactor based upon an ESI interface to a quadrupole mass spectrometer. Two types of systems were explored: (1) proteins possessing cysteine-cysteine disulfide bonds and the analogous disulfide-reduced proteins, and (2) proteins sprayed from solution compositions where the protein has different conformations. While the cysteine-cysteine disulfide-bound proteins were more reactive than equally charged disulfide-reduced proteins under these conditions, no significant reactivity differences were noted for ions arising from different solution conformations. The effect of inlet/reactor temperature on charge distributions with and without amine reagent was also explored, demonstrating that thermal denaturation of proteins can occur in heated capillary inlets. The results are discussed in the context of recent results indicating the persistence of at least some higher order protein structure in the gas phase.