LC/MS at the whole protein level: Studies of biomolecular structure and interactions using native LC/MS and cross-path reactive chromatography (XP-RC) MS.

Interfacing liquid chromatography (LC) with electrospray ionization (ESI) to enable on-line MS detection had been initially implemented using reversed phase LC, which in the past three decades remained the default type of chromatography used for LC/MS and LC/MS/MS studies of protein structure. In contrast, the advantages of other types of LC as front-ends for ESI MS, particularly those that allow biopolymer higher order structure to be preserved throughout the separation process, enjoyed relatively little appreciation until recently. However, the past few years witnessed a dramatic surge of interest in the so-called "native" (with "non-denaturing" being perhaps a more appropriate adjective) LC/MS and LC/MS/MS analyses within the bioanalytical and biophysical communities.

Influence of glycan modification on IgG1 biochemical and biophysical properties.

Monoclonal antibodies (mAbs) are the fastest growing class of biopharmaceuticals. The specific therapeutic tasks vary among different mAbs, which may include neutralization of soluble targets, activation of cytotoxic pathways, targeted drug delivery, and diagnostic imaging. The specific therapeutic goal defines which interactions of the antibody with its multiple physiological partners are most critical for function, and which ones are irrelevant or indeed detrimental.

Integration of On-Column Chemical Reactions in Protein Characterization by Liquid Chromatography/Mass Spectrometry: Cross-Path Reactive Chromatography.

Profiling of complex proteins by means of mass spectrometry (MS) frequently requires that certain chemical modifications of their covalent structure (e.g., reduction of disulfide bonds), be carried out prior to the MS or MS/MS analysis.

Assessing the iron delivery efficacy of transferrin in clinical samples by native electrospray ionization mass spectrometry.

Serum transferrin is a key player in iron homeostasis, and its ability to deliver iron to cells via the endosomal pathway critically depends on the presence of carbonate that binds this protein synergistically with ferric ion. Oxalate is another ubiquitous anionic species that can act as a synergistic anion, and in fact its interaction with transferrin is notably stronger compared to carbonate, preventing the protein from releasing the metal in the endosomal environment. While this raises concerns that high oxalate levels in plasma may interfere with iron delivery to tissues, concentration of free oxalate in blood appears to be a poor predictor of impeded availability of iron, as previous studies showed that it cannot displace carbonate from ferro-transferrin on a physiologically relevant time scale under the conditions mimicing plasma.