DSIP

1 Identity

Synthetic linear nonapeptide — endogenous neuropeptide with no established receptor. and delta-sleep inducing nonapeptide. which is the International Nonproprietary Name for the same molecule. Originally isolated by Schoenenberger and Monnier from cerebral venous blood of sleep-induced rabbits in the 1970s. The name is a 1970s hypothesis about a rabbit dialysate; it is not a mechanism and this catalog does not treat it as one.

Sequence

H-Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu-OH (WAGGDASGE). All-L nonapeptide, free N-terminal alpha-amine, free C-terminal carboxylic acid. No cysteine, no disulfide, no D-residue, no non-proteinogenic residue, no terminal cap. Gly3, Gly4 and Gly8 are achiral, so the molecule has six stereocenters and not nine. Two side-chain carboxylates (Asp5 and Glu9) plus the C-terminal carboxylate against a single alpha-amino group, so the peptide is strongly acidic and binds cationic counterion poorly but is routinely isolated as the acetate or trifluoroacetate of the single amine. The N-terminal tryptophan is the only aromatic residue and gives a genuine 280 nm chromophore, and it is also the photo-oxidation-sensitive feature. Sequence, formula, weight and CAS are verified under the International Nonproprietary Name Emideltide against NCATS, ChemSpider and a reagent catalog entry; Emideltide and DSIP are the same molecule, and that cross-name route to the verification is stated on the face of this record rather than left implicit.

Molecular formula

C35H48N10O15 (free acid). One seller states the acetate as C35H48N10O15 . XC2H4O2, which is the correct way to write a salt of undeclared stoichiometry and is the convention this catalog follows. The counterion is a label-claim matter and not a documentation nicety, because net peptide content is the claim.

Average mass

848.824 Da from the nonapeptide composition on IUPAC 2021 conventional atomic weights. RECONCILIATION, because three different numbers circulate for this molecule and all three are right: 848.814, a seller's printed 848.8, and 848.824. The 0.010 Da difference between 848.814 and 848.824 is entirely the atomic-weight convention — the older values (C 12.0107, H 1.00794, N 14.0067, O 15.9994) give 848.8136 and the 2021 conventional values (C 12.011, H 1.008, N 14.007, O 15.999) give 848.8240. It is not an arithmetic error in either place.

Monoisotopic mass

848.33006 Da neutral. Working ions: [M+H]+ m/z 849.33734, [M-H]- m/z 847.32278, [M+2H]2+ m/z 425.17231, [M+Na]+ m/z 871.31928. A plus or minus 5 ppm window on the neutral is plus or minus 0.0042 Da. Negative mode is the sensible primary on a peptide with three carboxylates and one amine; positive mode is retained because the C-terminal amide substitution noted below is 0.98 Da light and must be excluded at high resolution. That substitution sets the identity method: it must be high resolution, and a unit-resolution result does not clear release.

Salt / variant note

Multi-molecule name — five chemically distinct articles circulate across the DSIP and emideltide shelf, each separable by arithmetic. (1) Free acid, the INN article and this record: C35H48N10O15, 848.824 avg / 848.33006 mono. (2) C-terminal amide, WAGGDASGE-NH2: C35H49N11O14, 847.840 avg / 847.34605 mono — 0.98 Da light, invisible on a unit-resolution quadrupole, and the single likeliest wrong molecule to pass a nominal-mass identity test. This is the substitution that decides whether the identity method is fit for purpose. (3) N-acetyl DSIP free acid: C37H50N10O16, 890.861 avg / 890.34063 mono, +42.037 on the parent, cataloged separately by this company and stocked on the same shelves. (4) Salt forms: the acetate and the trifluoroacetate of the same peptide differ materially in net peptide content, and one seller writes the acetate as C35H48N10O15 . XC2H4O2 with the stoichiometry left as X, which is honest and is the convention to require. (5) Deletion and truncation sequences from solid-phase synthesis; des-Gly at -57.02 Da and des-Ala at -71.04 Da are the common ones on a sequence containing three Gly and two Ala.

2 Class & testing panel

Form

Single article

Testing panel

P1 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

Study types and identifiers only. Bibliometric: PubMed indexes 518 records for 'delta sleep-inducing peptide' spanning 1977 to 2026; publication volume is not evidence of efficacy, and most of the corpus is animal and biochemical work. Human interventional literature: approximately nine studies, all dated 1981 to 1992, most from one group in Basel; nothing interventional in humans in the last three decades. The two best-controlled are Monti and colleagues, Int J Clin Pharmacol Res 1987, PMID 3583493 — double-blind crossover polysomnographic randomized controlled trial in chronic insomniacs, intravenous, four nights; and Bes and colleagues, Neuropsychobiology 1992, PMID 1299794 — double-blind matched-pairs parallel-group study, 16 patients, five consecutive laboratory nights. The authors' own stated conclusions are not paraphrased in this record. Reviews: Graf and Kastin, Neurosci Biobehav Rev 1984, PMID 6145137; Graf and Kastin, Peptides 1986, PMID 3550726; Kovalzon and Strekalova, J Neurochem 2006, PMID 16539679. No identified receptor is established in the primary literature located. No approval in any jurisdiction and no marketed product anywhere. Evidence grade D.

4 Storage & specification

Storage

Lyophilized powder, acetate salt preferred over trifluoroacetate and specified on the purchase order. Store at -20 degrees C or below, desiccated, in amber or foil-overwrapped vials. The N-terminal tryptophan is photo-oxidation sensitive and the powder is hygroscopic, so light and moisture control are release-relevant and not housekeeping. Warm sealed vials to room temperature inside the desiccator before opening, to prevent condensation onto cold powder; on an 849 Da peptide the water taken up in that moment moves the net peptide claim, and the net peptide claim is the label.

Shelf life

Provisional 24-month retest interval at -20 degrees C, desiccated, in the sealed primary container. Provisional and labeled as such: the number is set from the general solid-state behavior of unmodified linear peptides, not from data on this material. It is replaced by the company's own ICH-format stability study, which places lot 1 on long-term (-20 degrees C) and accelerated (25 degrees C and 60 percent relative humidity) arms with pulls at 0, 3, 6, 12, 18 and 24 months; the first in-house pull that fails shortens the interval to the last passing point. Tracked attributes: tryptophan oxidation (+15.995 Da), water content and counterion. The Asp5-Ala6 bond is not a deamidation hotspot in the way an Asn-Gly would be, but Asp-containing sequences are watched for succinimide formation at low pH.