Two Elution Mechanisms of MEP Chromatography

Abstract

MEP (mercapto-ethyl-pyridine) HyperCel is one of the hydrophobic charge induction chromatography (HCIC) resins. Under normal operation, proteins are bound to the MEP resin at neutral pH, at which MEP is not charged, mostly via hydrophobic interaction. MEP has a pyridine group, whose pK is 4.8, and hence is positively charged at acidic pH range. Based on the binding mechanism (i.e., hydrophobic interaction) and the induced positive charge at acidic pH, there may be two ways to elute the bound proteins. One way is to bring the pH down to protonate both MEP resin and the bound protein, leading to charge repulsion and thereby elution. Another way is to use hydrophobic interaction modifiers, which are often used in hydrophobic interaction chromatography, to reduce hydrophobic interaction. Here, we summarize such two possible elution approaches.

Extraction and purification of ustiloxin A from rice false smut balls by a combination of macroporous resin and high-speed countercurrent chromatography

“…TFA was added to the eluting solvent and greatly improved the elution capacity. We assumed that TFA inhibited the ionization of UstA and promoted the dissolution of UstA molecules in methanol solution, similar to the cases reported before (Arakawa et al 2019;Tanaka et al 1999).…”