Disulfide rich peptides have gained significant attention recently due to their incredible biological stability and tolerance to epitope grafting. This class of peptides is often folded in solution, assuming the desired disulfide bond pattern correlates with the most thermodynamically stable structure. Sometimes though, especially for chemically synthesized cysteine rich peptides, this is not the case. The result is a complex mixture of peptides with varying disulfide bonding patterns and identical mass.
Resins for solid phase peptide synthesis can vary significantly in both functionalization and composition, leading to mixed results at the end of a synthesis. Previously, I demonstrated how the resin loading level affects the success or failure of your peptide synthesis.
In today’s post, I’ll highlight how both the hydrophilicity and swelling capacity of your resin can influence your peptide synthesis.
When it comes to synthesizing a peptide, the first thing that comes to mind is the number of stoichiometric equivalents to use. Sometimes that number is as few as 1.5, sometimes it’s as high as 20!
But have you ever thought about the liquid volume that contains those molecules and how that might affect the success of your coupling reaction? In this post I will discuss the impact of amino acid concentration in the overall success of solid phase peptide synthesis.
It used to be easy with only polystyrene based resin types, but nowadays there is a broad choice of types to choose from, including everything from the C-terminal functionality (Rink vs Wang) to the polymer from which the resin itself is synthesized.
All resins have one thing in common, and that’s the reactive site loading level. In this post, I will share my experiences with how this important factor impacts the success of peptide synthesis.
Reversed phase flash chromatography is increasingly being utilized by peptide chemists to decrease purification time and efforts. The larger particles used in flash columns enable large crude sample loads and can lead to highly pure peptide samples despite lower resolution when compared to traditional HPLC methods. However, there are some situations where the purity achieved isn't sufficient. Then what can you do?
In today's post, I'll describe using a focused gradient to achieve higher purity peptides than is possible with a more traditional linear gradient.
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.
In my role as a peptide application scientist, I have had the pleasure of working with many groups that are venturing into the world of peptides for the first time. Although it seems rather straightforward to experienced synthetic chemists, producing acceptable yield and purity certainly comes with unique challenges in solid phase peptide synthesis .
In this post I would like to present some of the tips and tricks that I have picked up along the way.
In the past, when I have synthesized a new peptide, I always ran a “scout run” – a small scale injection, usually with an analytical HPLC column – to both get an idea of the crude purity and also to identify a shorter, more optimal gradient for the actual purification. This strategy is still recommended when you want to use reversed phase flash chromatography for your purification strategy, but is there a better way?
In today’s post, I’ll discuss using a scouting column to screen gradient conditions prior to peptide purification with reversed phase flash chromatography.
More and more groups are exploring the utility of peptides with an ever widening variety of applications. And although peptides are getting cheaper to purchase outright, many groups are continuing to bring peptide synthesis in house. As more groups join the peptide community, I frequently encounter questions about the basics of peptide synthesis.
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.
Recently there has been substantial motivation to consider and evaluate alternative, more environmentally friendly solvents. Some countries have even gone so far as to ban some of the more toxic, yet commonly used solvents. In addition to general toxicity, additional consideration in the green chemistry movement is the volume of solvent used in any particular application. In this regard, purification solvent selection is closely monitored as they are often used in large quantities.