Ion mobility-mass correlation trend line separation of glycoprotein digests without deglycosylation

A high-throughput ion mobility mass spectrometer (IMMS) was used to rapidly separate and analyze peptides and glycopeptides derived from glycoproteins. Two glycoproteins, human α-1-acid glycoprotein and antithrombin III were digested with trypsin and subjected to electrospray traveling wave IMMS analysis. No deglycosylation steps were performed; samples were complex mixtures of peptides and glycopeptides. Peptides and glycosylated peptides with different charge states (up to 4 charges) were observed and fell on distinguishable trend lines in 2-D IMMS spectra in both positive and negative modes. The trend line separation patterns matched between both modes. Peptide sequence was identified based on the corresponding extracted mass spectra and collision induced dissociated (CID) experiments were performed for selected compounds to prove class identification. The signal-to-noise ratio of the glycopeptides was increased dramatically with ion mobility trend line separation compared to non-trend line separation, primarily due to selection of precursor ion subsets within specific mobility windows. In addition, isomeric mobility peaks were detected for specific glycopeptides. IMMS demonstrated unique capabilities and advantages for investigating and separating glycoprotein digests in this study and suggests a novel strategy for rapid glycoproteomics studies in the future

Never Waste a Good Crisis: An Historical Perspective on Comparative Corporate Governance

Different economies at different times use different institutional arrangements to constrain the people entrusted with allocating capital and other resources. Comparative financial histories show these corporate governance regimes to be largely stable through time, but capable of occasional dramatic change in response to a severe crisis. Legal origin, language, culture, religion, accidents of history (path dependence), and other factors affect these changes because they affect how people and societies solve problems.agency problems, institutions, structural reform, family business groups, oligarchy, corporatism