DSIP (Emideltide)

This compound’s International Nonproprietary Name is emideltide. It is traded almost universally under the legacy laboratory acronym DSIP, and that acronym stands for a proposed effect rather than for anything chemical.

A note on the name, before anything else

The acronym expands to a phrase asserting a physiological effect. That expansion dates from the peptide’s original description decades ago and has been carried forward as a trade name ever since.

We list the compound under that name only because it is the term buyers search for. The name is not a claim, and nothing on this page states or implies that this material does anything. Reference suppliers handle the same problem in two ways: Cayman avoids the acronym entirely and titles the product emideltide, demoting DSIP to a searchable synonym; Bachem keeps the legacy title but pairs it with nothing except sequence, registry number, formula and storage, so the name functions as an inert historical label. This page follows both — the INN leads, and the description is confined to chemistry.

Identity and classification

No single receptor or molecular target is established for this peptide, and none is claimed. It is supplied and characterised as a sequence-defined reference peptide.

A phosphorylated variant is separately catalogued by reference suppliers, carrying a phosphate on the serine residue. It is a different compound with a different mass and registry number. If a certificate is ambiguous about which is supplied, the mass settles it — the phosphorylated form is 80 Da heavier.

Structure

Nine standard L-amino acids in ordinary linkage: Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, with a free N-terminal amine and a free C-terminal acid. Linear — no cyclisation, no disulfide bonds, no D-amino acids, no non-natural residues, no amidation.

Compositionally the peptide is acidic — an aspartate, a glutamate and the C-terminal carboxyl against no basic residue at all — and unusually glycine-rich, with three glycines out of nine. Both features shape its analysis.

Specification and characterisation

• The Asp-Gly motif at residues 5–6. This is the fastest-rearranging sequence context in peptide chemistry: aspartate followed by glycine readily forms a succinimide intermediate, which resolves to a mixture of aspartate and isoaspartate. The isoaspartyl product is isobaric — the same mass — so mass spectrometry cannot detect it, and reverse-phase separation of the two is often incomplete. This is the most important and least-reported specification point for this peptide. Detection requires isoaspartate-specific methods or careful peptide mapping.
• Tryptophan at position 1. The most photolabile standard residue, and here it is also the N-terminal residue and the only aromatic one — so it carries the entire 280 nm signal. Oxidation to N-formylkynurenine is a +32 Da change.
• RP-HPLC purity at 214 nm, with 280 nm informative solely via that single tryptophan.
• Mass confirmation against 848.8. Negative-ion mode often suits an acidic peptide better.
• Poor reverse-phase retention. Small, acidic and glycine-rich, the peptide is polar and elutes early. Method matters when reading an area-percent figure.
• Counter-ion and net peptide content. Commonly supplied as the acetate or trifluoroacetate.

Handling and stability

Store sealed at 2–8 °C, dry, protected from light. Light protection is specific, driven by the N-terminal tryptophan.

There is no cysteine and no methionine, so oxidative sulfur chemistry does not apply. The dominant chemical liability is the Asp-Gly rearrangement, which is accelerated at neutral to alkaline pH and by elevated temperature. As a dry, cool, sealed solid the peptide is stable; solution storage is where the risk lies.

Equilibrate in a desiccator before opening.

Related compounds in this library

Epitalon is the closest analogue in behaviour — another small, acidic, unmodified peptide carrying an Asp-Gly-adjacent rearrangement liability and poor reverse-phase retention. The two share almost all of the same analytical caveats.

References

Chemical, specification and analytical sources. This list is deliberately limited to chemistry and analytical references.

• Cayman Chemical, emideltide — formula, molecular weight, sequence, nomenclature
• Bachem, DSIP product record — specification and registry data
• ChemicalBook, CAS 62568-57-4 — registry and formula confirmation
• Bachem, Handling and Storage Guidelines for Peptides — aspartate rearrangement, tryptophan photolability

Cosmic Aminos supplies this material as a laboratory reagent for in-vitro research use only. It is not a drug, food, cosmetic or dietary supplement, is not approved by the Food and Drug Administration for any use, and is not for human or veterinary consumption. No dosing, administration or preparation guidance is provided.