Peptide Stability

Peptide degradation follows identifiable chemical pathways. Hydrolysis of peptide bonds accelerates with temperature and at extremes of pH. Methionine and cysteine residues oxidise. Asparagine and glutamine deamidate. Aggregation can follow agitation.

This is why handling advice is specific rather than general: each pathway is driven by a different condition.

Freeze-thaw

Repeated freezing and thawing of a solution concentrates solutes at ice boundaries and mechanically stresses the molecule. Aliquoting a reconstituted vial into single-use portions is the standard laboratory response.