Mass-directed purification, whether with a preparative HPLC or a bench-top flash system, is quickly gaining interest in the peptide purification space. The simple fact is that using a specific mass, rather that UV absorbance, to trigger fraction collection allows for greater confidence in the identity of the collected fraction. Importantly though, this technique can also reduce your time required for purification, by significantly reducing or even eliminating the need for secondary mass analysis of each collected fraction.
As the rules for cell permeability continue to be elucidated, peptides are increasingly being used to deliver either themselves or cargo to the cell’s interior. One thing is clear, increasing the overall cationic charge of the peptide enhances it’s delivery to not only the cytoplasm, but also the nucleus or other subcellular compartments. To achieve the positive charge, large numbers of arginine residues are most often incorporated into the peptide sequence.
This begs the question though, should I change my cleavage protocol? In today’s post, I’ll evaluate several lengths of time used to cleave and fully deprotect an Arg-rich peptide sequence.
We've all used mass spectrometry to characterize our synthetic peptides. It's often used to confirm that the peptide was in fact synthesized, then again as part of the purification process to make sure that we're collecting the correct peak. But how many of you had the opportunity to use in-line mass spectrometry as an integral component during the purification itself?
In today's post, I'll highlight some of the advantages to using in-line mass mass spectrometry for purification of peptides using reversed phase flash chromatography.