A cycle of freezing and thawing a substance, which can damage peptide structure through ice crystal formation and aggregation. Multiple freeze-thaw cycles significantly degrade peptides; aliquoting prevents this.
"Freeze-Thaw Cycle" is filed under Storage & Stability in the PeptideAtlas glossary, alongside 5 other terms in that group.
2 other glossary entries refer to this term in their own definition, which is usually the fastest way to see how it is used in practice.
A measured portion of a solution divided from a larger volume. Peptides may be aliquoted into single-use portions to avoid repeated freeze-thaw cycles.
The clumping together of peptide molecules, often caused by heat, agitation, or repeated freeze-thaw cycles. Aggregated peptides may lose potency and can trigger immune reactions if injected.
A common peptide degradation reaction where asparagine or glutamine residues lose an amide group. Accelerated by heat and alkaline pH. Detected on COAs as impurity peaks.
A degradation reaction where methionine, cysteine, or tryptophan residues in peptides react with oxygen. Exposure to light, air, or peroxides accelerates oxidation. Causes loss of potency.
Terms that reference this one: Aliquot, Aggregation.
More Storage & Stability terms: Aggregation, Deamidation, Oxidation, Desiccant, Beyond-Use Date (BUD).