Storage
Aggregation
Research use only. For in vitro research use only. Not for human or animal consumption. Not for human consumption, medical use, or personal application.
Aggregation is the self-association of peptide molecules into larger assemblies, from soluble dimers through to visible particulate. The process is physical rather than chemical: no bond within the sequence needs to break, so material can sit fully within its purity specification and still aggregate. The driver is exposed hydrophobic surface. Partially unfolded chains bury those surfaces against each other rather than against water, and once assembled the structures are often difficult to disperse again.
Conditions that push a peptide towards association
High concentration, pH near the isoelectric point, air-liquid interfaces generated by vigorous shaking, and the concentration effects of partial freezing all favour it. Some sequences associate readily at almost any concentration, which is usually evident from their handling notes.
Technique at the point of dissolving matters. Adding diluent down the vial wall and mixing gently limits interfacial stress; reconstitution basics and the way solubility varies between sequences are the background to that.
Consequences for assay work
Aggregated material is effectively absent from the working concentration, so results drift low with no obvious cause. Cloudiness, wisps in suspension or a film at the meniscus are the visible signs; soluble aggregates give none.
Because purity by HPLC reports what dissolves and reaches the column, an aggregation problem can pass a purity check and still ruin an experiment. The storage guide explains where freezing contributes.
Frequently asked questions
- Can aggregates be redissolved?
Partly, sometimes. Gentle warming or brief sonication under a validated method can break up loose associations, but mature particulate rarely returns to a monomeric state.
- Does aggregation affect lyophilised material?
It can begin during drying or in storage where moisture is present, though the visible problem usually appears only once the vial is in solution.
- Is a cloudy solution always aggregation?
No. Incomplete dissolution and particulate shed from a stopper look similar, so separate undissolved material from associated material before concluding anything.
Updated 2026-06-01