Multiplex isobaric tags (e.g., tandem mass tags (TMT) and isobaric tags for relative and absolute quantification (iTRAQ)) are a valuable tool for high-throughput mass spectrometry based quantitative proteomics. We have developed our own multiplex isobaric tags, DiLeu, that feature quantitative performance on par with commercial offerings but can be readily synthesized in-house as a cost-effecti...

Brachial artery diameter and compliance were measured in 23 normotensive control subjects and 49 hypertensive patients. The results were compared in isobaric conditions by a modeling analysis extrapolating from the measured data a short segment of the pressure-diameter and pressure-compliance curves in the artery. A logarithmic diameter-pressure function was used as well as measurements of brac...

Quantitative mass spectrometry (MS)-based proteomics has been employed to investigate various biological processes by measuring the relative and absolute expression levels of proteins in cells. These studies are enabled by tandem mass spectrometry (MS/MS)-based isobaric tags, made popular by their capability for multiple sample comparison in a single MS experiment. Here, we develop novel isobar...

Abstract Recent years have witnessed a surge of interest in learning representations graph-structured data, with applications from social networks to drug discovery. However, graph neural networks, the machine models for handling face significant challenges when running on conventional digital hardware, including slowdown Moore’s law due transistor scaling limits and von Neumann bottleneck incu...

Phosphatidylcholine (PC) species in human plasma are used as biomarkers of disease. PC biomarkers are often limited by the inability to separate isobaric PCs. In this work, we developed a targeted shotgun approach for analysis of isobaric and isomeric PCs. This approach is comprised of two MS methods: a precursor ion scanning (PIS) of mass m/z 184 in positive mode (PIS m/z +184) and MS3 fragmen...

Isobaric tagging techniques such as iTRAQ and TMT are widely used in quantitative proteomics and especially useful for samples that demand in vitro labeling. Due to diversity in choices of MS acquisition approaches, identification algorithms, and relative abundance deduction strategies, researchers are faced with a plethora of possibilities when it comes to data analysis. However, the lack of g...

Mass spectrometry imaging (MSI) by laser ablation electrospray ionization (LAESI) enables the lateral mapping of molecular distributions in untreated biological tissues. However, direct sampling and ionization by LAESI–MSI limits the differentiation of isobaric ions (e.g., structural isomers) in a complex sample. Ionmobility separation (IMS) of LAESI-generated species is sufficiently fast to be...

Distinctions between isobaric residues have been a major challenge in mass spectrometric peptide sequencing. Here, we propose a methodology for distinction among isobaric leucine, isoleucine, and hydroxyproline, a commonly found post-translationally modified amino acid with a nominal mass of 113 Da, through a combined electron transfer dissociation-collision-induced dissociation approach. While...