NN9535 Reference
Written by the Pure Peptides editorial team
Molecular Profile
Compound
NN9535
Also known as
Pure-SEM-1
CAS number
910463-68-2
Molecular formula
C187H291N45O59
Molecular weight
4113.6 g/mol (average)
Amino acid sequence
H-Aib-E-G-T-F-T-S-D-V-S-S-Y-L-E-G-Q-A-A-K*-E-F-I-A-W-L-V-R-G-R-G-OH (31 residues)
Side-chain modification
lysine 20 carries two AEEA units, then γ-glutamic acid, then octadecanedioic acid
C-terminus
free acid
Purity
99%
Physical form
Lyophilized powder
What NN9535 is, structurally
NN9535 is a 31-residue analog of human GLP-1(7-37), with a fatty-acid chain on the side chain of lysine 20. Two numbering conventions are in circulation: this page numbers from the peptide's own first residue, so the Aib at position 2 is position 8 in the parent numbering, and the modified lysine at 20 is position 26.
The specification checks out independently. Rebuilding the formula from the stated sequence and modifications gives C187H291N45O59 at 4113.6, matching the stated figures, and the deposited record named in the brief agrees. The nitrogen count reconciles separately: 31 backbone nitrogens (30 peptide-bond amides and the free N-terminal amine), eleven on side chains from a histidine, a lysine, a glutamine, a tryptophan and two arginines, and three in the linker. That is 45, with no C-terminal amide nitrogen because this molecule ends in a free acid.
Aib at position 2 bears two substituents on the alpha-carbon rather than one, so it has no alpha-hydrogen. Base-catalyzed epimerization proceeds by abstracting that hydrogen, so the position cannot racemize, and carrying two identical methyls it has no stereocenter there at all.
One substitution has a consequence worth drawing out. An arginine at position 28 replaces the lysine the parent sequence carries there, leaving exactly one lysine in the molecule. The acylation site is therefore unambiguous: no second lysine side chain could carry the chain instead or in addition, which makes the attachment position easier to establish analytically.
The acyl chain dominates the handling. An eighteen-carbon diacid, joined through gamma-glutamic acid and two AEEA spacers, gives an otherwise hydrophilic peptide a long hydrophobic tail, and amphiphiles do not behave in solution as peptides do.
Three consequences follow. Amphiphiles aggregate above a threshold concentration, so a concentrated stock and a dilute working solution may differ in what they contain. A hydrophobic tail partitions onto plastic and glass, so losses at low concentration can be substantial rather than a trace. And only one of the diacid's two carboxyls forms the amide to gamma-glutamic acid, leaving the other free and negatively charged at neutral pH.
The free C-terminus compounds that: where a C-terminal amide carries no charge, a free acid carries a negative one. With three glutamates and an aspartate in the sequence, and a free carboxyl on the gamma-glutamic acid, solubility improves toward neutral and mildly alkaline pH.
The weak points are visible in the sequence: one tryptophan, the most oxidation-prone residue present, one tyrosine, and one glutamine that can deamidate for about one mass unit. There is no cysteine and no methionine, so no disulfide chemistry and no sulfoxide route.
Structure at a glance
Pure-SEM-1: C 187, N 45, O 59.
Drawn from the product database.
Reconstitution and handling
Sterile water is the usual starting solvent, and neutral to mildly alkaline buffers suit an acidic, acylated peptide. Dilute acid, which helps many peptides dissolve, works against this one.
Add diluent slowly down the inside wall of the vial and swirl gently. Do not vortex; a surface-active molecule foams readily.
Use low-binding tubes and keep transfers few, for the reason above.
No reducing agent is needed, since the formula contains no sulfur.
This is laboratory preparation chemistry, not dosing, administration, or protocol guidance of any kind.
Storage and stability
Store the lyophilized powder at -20 degrees C, sealed, desiccated and protected from light. Reconstituted, hold at 2 to 8 degrees C, or aliquot and freeze rather than thawing repeatedly.
Tryptophan oxidation is the first named liability, with the tyrosine behind it; air, warmth and light accelerate both. Glutamine deamidation is the second, needs water, and is accelerated by warmth and alkaline pH.
Aggregation deserves mention because it is physical rather than chemical and no mass measurement reports it. Associated material may not redisperse on dilution, and freeze-thaw promotes it.
These are storage conditions for the material, not dosing or administration guidance.
How NN9535 is tested
Reversed-phase HPLC establishes chromatographic purity as area percent, and the acyl chain shifts expectations. An eighteen-carbon tail retains strongly on a C18 column, so a higher organic proportion is needed than for an unmodified peptide of this length.
Detection sits near 214 nm, and the tryptophan and tyrosine give usable absorbance near 280 nm.
Area percent is a chromatographic measure, not peptide content by weight: water and counter-ions also add to the weight of the powder.
Mass spectrometry confirms identity against 4113.6. At this size average and monoisotopic figures differ appreciably, so establish the reporting basis first. Sixteen units indicates oxidation, most likely at the tryptophan, and one unit deamidation.
These describe general methodology, not a claim about any particular batch.
Handling FAQ
Why is acid a worse idea here than on an amidated peptide?+−
Because it ends in a free acid rather than an amide, which carries a negative charge an amide does not. With three glutamates, an aspartate and the free carboxyls on the diacid and the gamma-glutamic acid as well, lowering the pH moves it toward poorer solubility.
Is there any doubt about which residue carries the fatty-acid chain?+−
No. The sequence contains exactly one lysine, since an arginine replaces the lysine the parent carries at position 28, leaving no second side chain the acyl group could occupy. Full specifications for Pure-SEM-1.
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