What DSIP is
DSIP is the name attached to the nonapeptide Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE), formula C35H48N10O15 and average mass about 848.8 g/mol, with a free N-terminal amine and a free C-terminal acid. The abbreviation dates from the 1970s, when the peptide was first isolated and sequenced, and it is a historical label rather than a description of the chemistry.
Compared with the tri- and tetrapeptides in our short-peptide group, DSIP differs in two ways. At nine residues it is more than twice their length, and it carries an aromatic residue, a tryptophan at the N-terminus, which none of them has. Six of its nine residues are glycine, alanine or serine, and with Asp, Glu and the C-terminal acid set against a single amine, its net charge near neutral pH is negative.
DSIP 2mg specification
| Catalog name | DSIP |
|---|---|
| Sequence | H-Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu-OH (WAGGDASGE) |
| Molecular formula | C35H48N10O15 |
| Average mass | approx. 848.8 g/mol |
| CAS number | 62568-57-4 |
| Amount per vial | 2 mg |
| Form | Lyophilized powder in a crimp-sealed vial |
| HPLC purity | ≥98% |
| Shelf life | 36 months, sealed |
How DSIP is analyzed
The tryptophan changes the analysis in useful ways. It gives DSIP enough hydrophobic surface to retain clear of the void on C18 under a shallow acetonitrile gradient, and its indole ring absorbs at 280 nm, so a second detection channel is available alongside the 214 nm purity read. Comparing the two channels helps flag impurities in which the tryptophan has been lost or modified. Tryptophan is also the likely oxidation site, giving species at +16 and +32 Da that typically elute a little earlier than the parent. The aspartate at position five can form an aspartimide during synthesis, seen 18 Da light, which may reopen to a same-mass isomer visible only as a closely eluting peak. The protonated parent should read near 849.
An independent reverse-phase HPLC analysis of DSIP is published on this page. There are no lot or batch marks on the vial, so use its crimp and cap color to pair it with that analysis.
Research contexts for DSIP
- Dual-wavelength (214/280 nm) HPLC method development for a single-tryptophan peptide
- Tryptophan oxidation tracking by LC-MS
- Aspartimide and isoaspartate resolution studies at an Asp-Ala junction
- Intrinsic tryptophan fluorescence measurements in cell-free peptide–protein binding assays
DSIP is supplied for in-vitro and analytical laboratory research, with no human or animal application intended.
DSIP questions
What does the name DSIP describe chemically?
Nothing. It is an abbreviation kept from the original isolation work. The sequence WAGGDASGE and a mass near 849 are what identify the compound.
Why is DSIP visible at 280 nm when many short peptides are not?
Its N-terminal tryptophan carries an indole ring that absorbs there. Purity is still reported at 214 nm, where every peptide species responds, with 280 nm serving as a cross-check.
Which impurities are most likely in a DSIP sample?
Oxidized tryptophan forms at +16 and +32 Da, aspartimide-related species from the Asp-Ala junction, and short deletion sequences from synthesis. Each should be resolved from the main peak rather than folded into it.
Buying DSIP 2mg in the USA
DSIP 2mg ships from within the United States with a tracking reference, and orders over $100 qualify for free shipping. Bulk pricing is offered for repeat assay work. DSIP is sold to research institutions, licensed researchers, universities and laboratory R&D purchasers, and to no other buyers. The compound’s identity and analysis are covered in What Is DSIP? Sequence, Identity and Analytical Profile.
Supplied for laboratory research only: DSIP 2mg is not for human or veterinary use.
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