Preparative scale mass spectrometry: A brief history of the calutron.

Calutrons were developed in the laboratory of E. O. Lawrence at the University of California at Berkeley.

Taurine Is Covalently Incorporated into Alpha-Tubulin.

Taurine is the most abundant free amino acid in the human body. It is found in relatively high concentrations (1-10 mM) in many animal tissues but not in plants. It has been studied since the early 1800s but has not been found to be covalently incorporated into proteins in any animal tissue.

Unbiased Thiol-Labeling and Top-Down Proteomic Analyses Implicate Multiple Proteins in the Late Steps of Regulated Secretion.

Regulated exocytosis enables temporal and spatial control over the secretion of biologically active compounds; however, the mechanism by which Ca modulates different stages of exocytosis is still poorly understood. For an unbiased, top-down proteomic approach, select thiol- reactive reagents were used to investigate this process in release-ready native secretory vesicles. We previously characterized a biphasic effect of these reagents on Ca-triggered exocytosis: low doses potentiated Ca sensitivity, whereas high doses inhibited Ca sensitivity and extent of vesicle fusion.

An efficient solution for resolving iTRAQ and TMT channel cross-talk.

Isobaric tagging reagents such as isobaric tag for relative and absolute quantitation (iTRAQ) and tandem mass tag (TMT) typically have isotopic impurities that cause significant cross-talk between channels. Here, we present an efficient solution to compensate for channel cross-talk using linear algebra and find that it is between 20× and 120× faster than previous methods. We also find that the effects of channel cross-talk are as important to manage as the effects of ratio compression because of precursor impurities, and we have released an open-source tool to perform both types of calculations.

Cyclodextrin and malto-dextrose collision cross sections determined in a drift tube ion mobility mass spectrometer using nitrogen bath gas.

In this study, we have evaluated a low field limit drift tube ion mobility device for ion mobility-mass spectrometry (IM-MS) measurements that uses nitrogen as a bath gas with electrospray ionization on a modified Q-TOF instrument. We have determined reduced mobility (K0) and collision cross section (CCS) values for a group of analyte ions that have been characterized previously in other drift tube IM-MS instruments. Our determinations of CCS for this set of ions as well as for standards are in agreement with published values.