Salt removal during Off-Gel? electrophoresis of protein samples

Abstract

The Off-Gel  technology was recently described for protein fractionation in a solution placed on top of an immobilized pH gradient gel. In addition, this process was found to remove salts from the biological samples to analyze. This desalting effect is studied experimentally in a conductometric prototype cell. A simplified analytical model is developed to understand this process and a good agreement is found with the conductivity measurements. To illustrate the desalting of a biological sample, a 1 mg?mL 21 solution of b-lactoglobulin A in 0.1 M NaCl is subjected to electrophoresis in a single compartment Off-Gel  cell. The analysis of the resulting sample by ESI-MS demonstrates the effective removal of salt. A finite element diffusion-migration model is also used to illustrate how the nonuniformity of the electric field in the cell, associated with the salt migration, can slow down the desalting process.

Peptides OFFGEL electrophoresis: a suitable pre-analytical step for complex eukaryotic samples fractionation compatible with quantitative iTRAQ labeling

“…For example, a combination of OFFGEL, Strong Cation Exchange (SCX) and nano RP chromatographies seems to be an interesting approach to apprehend the complexity of the plasma. An another advantage of OFFGEL is its ability to desalt the sample during separation which can avoid in certain processes a supernumerary desalting step [ 15 ].…”

Proteomics study of anthrax lethal toxin‐treated murine macrophages

“…The advantage is that it greatly facilitates further analysis without subsequent steps such as purification or extraction, which can lead to sample loss. For example, it has previously been shown that this technique is particularly suited to the removal of salts from the sample buffer, which can aid in mass spectrometric analyses [42].…”

Isolation and characterization of glycosylated neuropeptides

“…Besides endogenous peptides, biological samples usually also contain lipids, salts and large proteins (Aebersold & Mann, 2016;Arnaud et al, 2005;Cajka & Fiehn, 2016;Paglia, Kliman, Claude, Geromanos, & Astarita, 2015). They will interfere the ionization efficiency, contaminate the LC platform and suppress the signal intensity of target peptides.…”