CJC-1295 with DAC Specs: Sequence, MW & CAS
Part of the full CJC-1295 with DAC guide - a synthetic growth-hormone-releasing hormone reference compound, identity-verified with a COA on every vial.
In brief
The molecular specification of CJC-1295 with DAC tells the story of a peptide engineered in two layers: a recognizable GHRH backbone and a bolted-on albumin-binding cap. The sequence is a 30-residue chain, Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-Lys, whose backbone is GRF(1-29) carrying four deliberate substitutions, D-Ala2, Gln8, Ala15 and Leu27, plus a C-terminal Lys30 bearing an Nepsilon-maleimidopropionyl DAC linker. The entry lists a free pre-conjugation molecular weight near 3647 g/mol, commonly cited around 3647.8 g/mol, a molecular formula of C165H269N47O46 (PubChem CID 91971820, with some vendors listing C165H271N47O46), and CAS number 863288-34-0. After conjugation to roughly 66.5 kDa albumin the effective circulating mass rises to about 70 kDa. Each of these identifiers encodes a specific structure-function fact, and this spoke reads them in that light.
To the molecule
Molecular specifications
Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-Lys (30 residues; backbone = GRF(1-29) with substitutions D-Ala2, Gln8, Ala15, Leu27, plus a C-terminal Lys30 bearing an Nε-maleimidopropionyl DAC linker). One-letter core (substitutions noted): Y-[D-A]-DAIFT-Q-SYRKVL-A-QLSARKLL-QDI-L-SR-KThe detail
A closer look
01
Sequence and the four substitutions
The 30-residue sequence is best read as sermorelin's GRF(1-29) scaffold plus engineering. The first 29 residues correspond to the natural GHRH fragment that supplies GHRHR agonism, while four positions are deliberately altered. D-Ala2 replaces the native L-alanine with its D-enantiomer at the position-2 site that proteases attack; Gln8, Ala15 and Leu27 are the three further substitutions. The entry attributes these collectively to conferring resistance against dipeptidyl-peptidase-IV and other proteolytic cleavage in vitro. The structure-function reading is that these changes preserve receptor recognition, since the molecule remains a GHRHR ligand, while hardening the backbone against enzymatic degradation. The C-terminal Lys30 is the thirtieth residue added specifically as an attachment point: its side-chain amine carries the maleimidopropionyl group, separating the receptor-binding function of residues 1 to 29 from the conjugation function localized at position 30.
02
Molecular weight, formula and the albumin shift
The cited free molecular weight near 3647 g/mol describes the pre-conjugation DAC peptide, the form a lab handles before any albumin coupling. That mass is the appropriate figure for converting a reconstituted mass-based stock into molarity for in-vitro assays. The molecular formula C165H269N47O46 is tied to PubChem CID 91971820 for the maleimidopropionyl-Lys30 DAC molecule, and the entry explicitly flags that the value is treated as primary while some vendor sources list C165H271N47O46 and that formula listings vary across non-authoritative vendors. The dramatic specification change comes at conjugation: once the maleimide reacts with albumin Cys34, the effective circulating mass jumps to roughly 70 kDa because the peptide now travels covalently bound to a ~66.5 kDa carrier protein. The same molecule therefore has two relevant masses depending on whether it is free in the vial or albumin-conjugated.
03
CAS identity and class placement
CAS number 863288-34-0 is the registry identifier that disambiguates this specific DAC molecule from related analogs such as the unmodified GRF(1-29) backbone or other ConjuChem conjugates. Paired with PubChem CID 91971820, it gives a research lab two authoritative handles for sourcing and verification, which matters because, as the entry notes, vendor formula listings vary. In class terms the specifications place the molecule as a synthetic growth-hormone-releasing hormone (GHRH/GRF) analog and, more specifically, an albumin-binding long-acting secretagogue peptide, the DAC standing for Drug Affinity Complex. The full picture from the spec card is internally consistent: a DPP-IV-resistant GRF(1-29)-derived agonist sequence, a defined free mass and formula, a CAS and CID for identity, and a maleimide-Lys30 cap that converts the peptide into a ~70 kDa albumin bioconjugate in circulation.
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. CJC-1295 with DAC 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.