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Molecular Weight
Purity
Storage
Appearance
Solubility
01
CJC-1295 with DAC is a long-acting analogue of growth hormone-releasing hormone (GHRH). It is built on the same tetrasubstituted GHRH(1–29) backbone as CJC-1295 (No DAC), with one addition: a lysine at position 30 whose side chain carries a maleimidopropionic acid (MPA) group. This group is the “Drug Affinity Complex”, or DAC.
The maleimide reacts with the single free cysteine (Cys34) of serum albumin, forming a stable covalent bond. Once attached, the peptide effectively rides on albumin, which is the basis of its much longer persistence in research models compared with the unconjugated peptide. It is supplied as a lyophilized reference material for in vitro work on maleimide–albumin conjugation, sustained receptor engagement and comparative studies with the No DAC analogue and native GHRH.
02
The receptor-binding part of the molecule is identical to CJC-1295 (No DAC), including its four stabilising substitutions: D-Ala2, Gln8, Ala15 and Leu27. The differences are all at the C-terminus.
Added Lys30
An extra lysine extends the sequence to 30 residues. Its side-chain amine is the attachment point for the linker, and the new C-terminus is amidated.
Maleimide group
The MPA group ends in a maleimide ring that reacts selectively with free thiols at near-neutral pH. In serum-containing media, albumin Cys34 is the dominant partner, giving a 1:1 peptide–albumin conjugate.
Linker position
The linker is at the far end from the N-terminal region that binds the GHRH receptor, so attachment to albumin does not block receptor recognition.
Maleimide hydrolysis
In water the maleimide ring can slowly open to a maleamic acid form (+18 Da), which no longer reacts with thiols. How much of each form is present is an important quality attribute.
03
In vitro research treats CJC-1295 with DAC as a GHRH receptor agonist whose distinguishing feature is its ability to attach to albumin.
Conjugation kinetics
Incubating the peptide with albumin and monitoring adduct formation by HPLC or MS over time, pH and albumin concentration gives rate data for the maleimide–thiol reaction.
Receptor binding
Competition binding assays with GHRH receptor-expressing membranes compare free peptide, albumin-conjugated peptide and the No DAC analogue.
Sustained signalling
Cell-based cAMP assays compare how long receptor activation persists with albumin-bound versus free peptide.
Serum stability
Timed samples from serum incubations measure the proportions of conjugated peptide, free peptide and degradation products.
All observations described here come from cell-free and cell-based in vitro systems.
04
Conjugation reference standard
Used to benchmark the rate and selectivity of maleimide–thiol coupling under biologically relevant conditions.
Comparator to the No DAC form
Paired with CJC-1295 (No DAC) in time-course studies to isolate the effect of albumin binding.
Half-life extension case study
A well-known example of the albumin-binding strategy for extending peptide persistence, used when designing or comparing similar approaches.
Analytical method development
The free peptide (about 3.6 kDa) and its albumin conjugate (roughly 70 kDa) call for different techniques, including RP-HPLC, size-exclusion chromatography, SDS-PAGE and intact-protein MS, making it a useful test case for mixed peptide/protein workflows.
05
Storage
Store the lyophilized powder at −20 °C, sealed and desiccated. Moisture promotes maleimide ring opening, so keeping the material dry is especially important.
Reconstitution
Dissolve in water or a neutral, thiol-free buffer shortly before use. Avoid reducing agents and thiol-containing additives such as DTT, TCEP and β-mercaptoethanol, which react with the maleimide.
Solution stability
Ring opening speeds up as pH rises above about 7.5. Use solutions promptly and avoid holding them at room temperature or 4 °C for long periods.
Aliquots
If storage is needed, freeze single-use aliquots at −20 °C and avoid repeated freeze–thaw cycles.
Labware
Use low-binding polypropylene tubes and tips, and prepare buffers without free thiols.
06
Analysis must confirm the peptide sequence and also the state of the maleimide group.
HPLC
Reversed-phase C18 with a wide-pore (300 Å) column and a shallow acetonitrile gradient. The ring-opened maleimide form usually appears as a separate, nearby peak.
Mass spectrometry
ESI-MS should match about 3647 Da for the intact peptide, seen across several charge states. The hydrolysed maleimide form appears at +18 Da. Albumin conjugates need intact-protein MS.
Maleimide reactivity
A sample is reacted with a known thiol, such as cysteine or glutathione, and analysed by HPLC. The proportion that forms the thiol adduct shows how much maleimide is still active.
D-Ala2 verification
As with the No DAC form, the D-configuration is confirmed by chiral amino acid analysis or chiral chromatography, since MS cannot distinguish D from L.
Impurity profile
Typical impurities include the ring-opened maleimide form, the non-amidated (free-acid) C-terminus, truncated sequences and residual synthesis reagents.
07
Both share the same modified 29-residue GHRH sequence. The DAC form adds a lysine at position 30 carrying a maleimide linker that binds covalently to serum albumin. This raises the molecular weight from 3367.9 to about 3647 g/mol and changes how long the peptide persists in research systems.
A sample is reacted with a known thiol, such as cysteine or glutathione, and analysed by HPLC or MS. The proportion converted to the thiol adduct shows how much maleimide is still reactive, while the +18 Da ring-opened form shows how much has hydrolysed.
Reagents such as DTT, TCEP and β-mercaptoethanol contain or generate free thiols that react with the maleimide, using it up before it can bind albumin in the experiment.
The ring-opened form is measured by HPLC and MS (+18 Da) and reported as a specified impurity on the certificate of analysis. Acceptance limits are set in each lot specification.
No. It is supplied strictly as a reference compound for laboratory and analytical research and is not for human or animal use.
CJC-1295 (With DAC) Research Reference. (2026). Pure Peptides Labs Research Catalogue. Retrieved from https://purepeptideslabs.net/research-catalogue/growth-hormone-axis-research-peptides/cjc-1295-with-dac/
Materials listed on this platform are supported by independent testing and published documentation for laboratory research contexts.
