Oxidation
Definition
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.
What this means for research sourcing
Correct storage preserves peptide integrity between experiments. Volta product pages list compound-specific storage conditions and shelf life.
Related Terms in Storage & Stability
Freeze-Thaw Cycle
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.
Aggregation
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.
Deamidation
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.
Desiccant
A moisture-absorbing substance (typically silica gel) included in peptide packaging to prevent humidity-driven degradation during storage of lyophilized powders.
Beyond-Use Date (BUD)
The date after which a compounded preparation should not be used. Determined by the compounding pharmacy based on stability data. Differs from expiration date, which applies to manufactured drugs.