Semaglutide Specs: Sequence, MW & CAS
Part of the full Semaglutide guide - a acylated glp-1 receptor agonist reference compound, identity-verified with a COA on every vial.
In brief
Semaglutide's molecular specification, taken directly from the provided entry, gives a precise structural fingerprint: molecular formula C187H291N45O59, average molecular weight 4113.58 g/mol (about 4114 Da), CAS Registry Number 910463-68-2, PubChem CID 56843331, and DrugBank ID DB13928. Its peptide class is an acylated GLP-1 receptor agonist, an incretin mimetic and long-acting glucagon-like peptide-1 analogue. The sequence is a 31-residue analogue built on the human GLP-1(7-37) backbone with about 94% sequence homology, carrying an Aib8 substitution, an Arg34 substitution, and a Lys26 acylation with a C18 fatty-diacid through a gamma-Glu/2x-AEEA/OEG linker. This spoke explains what each specification means and how the sequence, mass, formula, and registry identifiers connect to structure-function, so a researcher can interpret a certificate of analysis and cross-reference authoritative chemical databases against the identity of the material in hand.
To the molecule
Molecular specifications
H-His-Aib-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Val-Ser-Ser-Tyr-Leu-Glu-Gly-Gln-Ala-Ala-Lys(modified)-Glu-Phe-Ile-Ala-Trp-Leu-Val-Arg-Gly-Arg-Gly-OH (31-residue GLP-1(7-37) backbone with Aib8 and Arg34 substitutions; Lys26 acylated with a C18 fatty-diacid via a gamma-Glu/2x-AEEA/OEG linker). One-letter backbone reference (pre-modification): H-Aib-EGTFTSDVSSYLEGQAAKEFIAWLVRGRGThe detail
A closer look
01
Sequence and structure-function determinants
The backbone is a 31-residue analogue of human GLP-1(7-37) with roughly 94% sequence homology, meaning the receptor-recognition core of the native incretin is largely conserved. The one-letter pre-modification reference (H-Aib-EGTFTSDVSSYLEGQAAKEFIAWLVRGRG) shows the two principal substitutions in context. Position 8 carries alpha-aminoisobutyric acid (Aib) in place of the native residue, the change responsible for DPP-4 cleavage resistance. Position 34 carries arginine (Arg34) in place of lysine, which removes a competing lysine so that acylation is directed site-specifically. The functional payload sits on Lys26: a C18 fatty-diacid side chain attached via a gamma-Glu/2x-AEEA (OEG) linker, the element that drives reversible albumin binding. This is a clear structure-function map in which each sequence-level change corresponds to a defined biochemical property: stability, acylation specificity, and protraction respectively.
02
Molecular formula and mass interpretation
The molecular formula C187H291N45O59 encodes the full acylated molecule, including the fatty-diacid side chain and its gamma-Glu/2x-AEEA linker, not merely the bare peptide backbone, which is why the atom counts and mass are larger than a 31-residue unmodified peptide would predict. The reported average molecular weight is 4113.58 g/mol (the entry notes a reported range of 4113.58-4113.64, approximately 4114 Da). Average molecular weight, the natural-isotope-abundance-weighted mass, is the appropriate figure for solution-preparation calculations such as converting milligrams to millimoles. For a researcher, this mass is the conversion constant that turns a gravimetric stock concentration into a molar one, which matters because receptor-pharmacology readouts and the reported approximately 0.38 nM binding affinity are expressed in molar units.
03
Registry identifiers and database cross-referencing
The specification includes several authoritative identifiers that let a laboratory verify material identity independently. CAS Registry Number 910463-68-2 is the unique chemical-substance identifier used across chemical suppliers and inventories. PubChem CID 56843331 links to the public compound record carrying the C187H291N45O59 formula, and DrugBank ID DB13928 provides a curated database entry. The entry's source hints additionally reference an FDA CDER/ChemR review context and Wikipedia's molar-mass listing of 4113.641, consistent with the stated average mass. Cross-referencing a vial's certificate of analysis against the CAS number and PubChem CID is the standard way to confirm that supplied research material matches the intended molecular entity. These identifiers, together with the formula and mass, constitute a complete, verifiable specification for the acylated GLP-1 receptor agonist described in the entry.
The fine print: products are sold for laboratory research use only and are not for human or animal consumption. Bodily introduction into humans or animals is strictly prohibited by law. Semaglutide is not a drug and is not intended to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the FDA.