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Terminus Peptides

Laboratory standards

Storage conditions

The environmental factors that determine how a peptide preparation changes over time.

Storage conditions are part of the specification of a material, not an afterthought. A result obtained on material stored one way does not necessarily describe the same material stored another way, which is why storage is recorded rather than assumed.

The factors that matter

  • Temperature. Rates of chemical degradation rise with temperature, and repeated freeze–thaw cycling is a distinct stress from steady cold storage.
  • Moisture. Water enables hydrolysis and deamidation. Lyophilised material is hygroscopic, so seal integrity matters as much as ambient humidity.
  • Light. Ultraviolet and visible light drive photodegradation, particularly of aromatic residues.
  • Oxygen. Methionine and cysteine oxidise readily; headspace composition is therefore a real variable.
  • pH, in solution. Deamidation and hydrolysis rates are strongly pH-dependent.
  • Surface adsorption, in dilute solution. Peptides can be lost to container walls, which reduces concentration without any chemical change.

References