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CJC-1295 No DAC
Technical Compound Reference | Orion Peptides Research Library
CJC-1295 No DAC is the common research-market name for Modified GRF (1-29), a synthetic 29-amino-acid analog of growth hormone-releasing hormone (GHRH).
Its chemical structure contains four amino acid substitutions relative to the corresponding natural GHRH fragment. These substitutions occur at positions 2, 8, 15, and 27.
The molecule has a linear peptide backbone, a C-terminal amide, and no Drug Affinity Complex (DAC).
The absence of DAC is an important structural distinction. The original CJC-1295 construct incorporates an additional chemical group designed to form a covalent connection with albumin. Modified GRF (1-29) lacks this reactive attachment.
In laboratory research, the non-DAC peptide is characterized through molecular mass analysis, sequence identification, chromatographic separation, and receptor-related experimental methods.
This reference examines its chemical identity, peptide modifications, relationship to GHRH, structural differences from DAC-containing analogs, analytical characterization, and stability considerations.
First, What Does “No DAC” Actually Mean?
The term DAC stands for Drug Affinity Complex.
It refers to a molecular modification developed to allow a peptide to form a chemical attachment to albumin.
The original CJC-1295 molecule uses a maleimide-containing chemical group connected through an additional lysine residue.
The maleimide group can react with a suitable thiol group on albumin, forming a covalent connection.
CJC-1295 No DAC does not contain this chemical attachment system.
Instead, it consists of the modified 29-residue GHRH fragment alone.
Why Is the Name Potentially Confusing?
In scientific literature, CJC-1295 has historically referred to the DAC-containing construct.
In research catalogs, the name CJC-1295 No DAC is commonly used for Modified GRF (1-29).
These materials share a related peptide backbone but are not identical molecules.
Therefore, the name CJC-1295 alone is insufficient to establish the exact chemical identity of a research material.
The sequence, molecular formula, and expected molecular mass should also be documented.
Molecular Identification
| Property | Reference information |
|---|---|
| Common name | CJC-1295 No DAC |
| Chemical designation | Modified GRF (1-29) |
| Alternative names | Mod GRF 1-29, Modified GHRH (1-29), tetrasubstituted GRF (1-29) |
| Commonly assigned CAS | 863288-34-0 |
| PubChem CID | 56841945 |
| Molecular formula | C₁₅₂H₂₅₂N₄₄O₄₂ |
| Average molecular weight | Approximately 3,367.9 g/mol |
| Amino acid count | 29 |
| Structural classification | Synthetic modified GHRH fragment |
| Backbone configuration | Linear |
| Amino acid substitutions | D-Ala², Gln⁸, Ala¹⁵, Leu²⁷ |
| N-terminal residue | Tyrosine |
| C-terminal residue | Arginine |
| C-terminal modification | Amidation |
| DAC modification | Absent |
| Cysteine residues | None |
| Disulfide bonds | None |
| Primary receptor family | GHRH receptor, class B GPCR |
| Primary analytical methods | RP-HPLC, LC-MS, MS/MS |
The reference formula describes the defined peptide molecule. Counterions, residual moisture, and other material-specific components must be considered separately.
1. The Peptide Sequence Behind Modified GRF (1-29)
The complete 29-residue sequence is:
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-NH₂
The corresponding abbreviated sequence can be written as:
Y-(D-Ala)-DAIFTQSYRKVLAQLSARKLLQDILSR-NH₂
The D-alanine at position 2 must be identified explicitly.
A conventional one-letter sequence does not always communicate amino acid stereochemistry.
Why Is the Sequence Important?
Two peptides can contain the same number of amino acids without having the same molecular structure.
Differences in amino acid order, stereochemistry, terminal modifications, and attached chemical groups can affect molecular properties.
For CJC-1295 No DAC, the sequence identifies four specific changes from natural GHRH (1-29).
It also confirms the absence of the additional DAC-containing lysine found in the original CJC-1295 construct.
What Does the Terminal NH₂ Mean?
The terminal NH₂ indicates C-terminal amidation.
In this modification, the peptide ends in a carboxamide rather than a free carboxylic acid.
C-terminal amidation forms part of the intended molecular structure and must be included when calculating molecular formula and mass.
2. Four Amino Acid Substitutions That Define the Molecule
Modified GRF (1-29) contains four deliberate changes relative to the natural GHRH (1-29) fragment.
These modifications influence its molecular structure and potential susceptibility to certain chemical or enzymatic changes.
| Position | Natural GHRH | Modified GRF (1-29) | Main structural distinction |
|---|---|---|---|
| 2 | L-Alanine | D-Alanine | Stereochemical inversion |
| 8 | Asparagine | Glutamine | Different amide side-chain length |
| 15 | Glycine | Alanine | Addition of a methyl-containing side chain |
| 27 | Methionine | Leucine | Removal of sulfur-containing thioether |
The combined sequence changes distinguish Modified GRF (1-29) from the unmodified GHRH fragment.
Position 2: D-Alanine
The second residue contains D-alanine instead of the natural L-alanine configuration.
Both forms have the same molecular formula.
However, their three-dimensional arrangements differ.
This stereochemical modification is associated with reduced susceptibility to certain N-terminal enzymatic cleavage processes.
Position 8: Glutamine
Glutamine replaces asparagine.
Both amino acids contain amide side chains, but glutamine includes an additional methylene group.
This changes the chemical structure without introducing a new functional-group category.
The substitution was incorporated into the modified GHRH analog design and may influence sequence stability.
Position 15: Alanine
Alanine replaces glycine.
Glycine has a hydrogen atom as its side chain.
Alanine contains a methyl group.
This substitution changes local backbone flexibility and molecular composition.
Because glycine is unusually conformationally flexible, replacing it can influence the spatial arrangements accessible to a peptide.
Position 27: Leucine
Leucine replaces methionine.
Methionine contains a sulfur-bearing thioether group that can undergo oxidation.
Leucine lacks this sulfur-containing functional group.
The substitution removes the specific methionine oxidation site present in the natural sequence.
However, this does not establish that the complete peptide is resistant to every oxidative degradation pathway.
3. Molecular Stereochemistry and Structural Identity
Stereochemistry describes the three-dimensional arrangement of atoms within a molecule.
It is particularly important for peptides because receptors and enzymes can distinguish between different amino acid configurations.
Modified GRF (1-29) contains D-alanine at position 2.
The remaining residues follow the specified L-amino-acid configurations of the reference structure, except where an amino acid does not have a chiral center.
Why Does D-Alanine Matter?
D-alanine and L-alanine have identical elemental compositions.
A substitution between the two does not change the molecular formula.
It can, however, influence the conformation of the peptide and its interactions with enzymes.
Can Intact Mass Spectrometry Identify D-Alanine?
Not by molecular mass alone.
An intact peptide containing D-alanine has the same theoretical mass as the corresponding L-alanine stereoisomer.
Additional methods may be needed when stereochemical identity is an important analytical requirement.
Is a Matching Molecular Weight Enough?
No.
A correct molecular mass supports identification but cannot establish every residue position or stereochemical feature.
Sequence-specific analysis and appropriate reference characterization provide stronger evidence.
4. The GHRH Receptor as a Molecular Research Target
Modified GRF (1-29) belongs to the GHRH analog family.
GHRH receptors are members of the class B G protein-coupled receptor family.
These receptors recognize peptide ligands and transmit extracellular signals into cells.
Ligand Recognition
A ligand is a molecule capable of binding to a specific molecular target.
The modified peptide backbone of CJC-1295 No DAC is related to the receptor-recognition region of GHRH.
This provides the structural basis for its classification as a GHRH receptor analog.
Receptor Activation
GHRH receptor activation is associated with Gs-dependent intracellular signaling.
This pathway can involve adenylyl cyclase and cyclic adenosine monophosphate (cAMP).
The cAMP molecule functions as an intracellular second messenger.
What Is Measured in Receptor Assays?
Laboratory experiments may measure changes in intracellular signaling across defined ligand concentrations.
Common parameters include:
| Parameter | Scientific meaning |
|---|---|
| Binding affinity | Ligand association with a receptor |
| EC50 | Concentration producing half-maximal measured response |
| Emax | Maximum response observed in an assay |
| cAMP activity | Intracellular second-messenger signaling |
| Receptor selectivity | Preference for a particular molecular target |
| Receptor internalization | Movement of receptor proteins into the cell |
A receptor-related response must be interpreted according to the experimental system.
Importantly, molecular design and activity demonstrated for DAC-containing CJC-1295 should not automatically be attributed to independently supplied No DAC material.
5. CJC-1295 No DAC vs CJC-1295 with DAC
The two compounds share a modified GHRH-related sequence but differ in their chemical architecture.
The original DAC-containing construct includes an additional lysine residue bearing a maleimidopropionyl group.
The No DAC compound lacks this modification.
Molecular Comparison
| Feature | CJC-1295 No DAC | CJC-1295 with DAC |
|---|---|---|
| Common chemical designation | Modified GRF (1-29) | DAC-GRF / CJC-1295 |
| Residues in peptide construct | 29 | 30 |
| Molecular formula | C₁₅₂H₂₅₂N₄₄O₄₂ | C₁₆₅H₂₆₉N₄₇O₄₆ |
| Average molecular weight | ~3,367.9 g/mol | ~3,647.2 g/mol |
| C-terminal amidation | Yes | Yes |
| Maleimide-containing modification | No | Yes |
| Designed covalent albumin attachment | No | Yes |
| Same chemical compound | No | No |
The mass difference between the reference molecules is approximately 279 Da.
This makes molecular mass an important analytical distinction.
What Does the DAC Modification Contribute?
The original DAC chemistry was designed to create a covalent attachment to a thiol group on serum albumin.
This interaction is chemically different from the noncovalent albumin association found in certain lipid-conjugated peptides.
The 2005 discovery study described the design and characterization of this albumin-reactive GHRH analog.
Why Must the Two Structures Be Distinguished?
A chromatographic or molecular-mass result corresponding to Modified GRF (1-29) cannot verify the presence of the DAC-containing construct.
Likewise, research conducted using the DAC-containing compound does not automatically establish the properties of the non-DAC structure.
Precise chemical identification is essential when comparing analytical data.
6. CJC-1295 No DAC vs Sermorelin
Sermorelin is another 29-residue GHRH-related peptide.
It corresponds to the unmodified GHRH (1-29) sequence with a C-terminal amide.
Modified GRF (1-29) contains the four substitutions described earlier.
Molecular Differences
| Characteristic | CJC-1295 No DAC | Sermorelin |
|---|---|---|
| Peptide length | 29 | 29 |
| Structural origin | Modified GHRH (1-29) | GHRH (1-29) |
| D-Ala at position 2 | Yes | No |
| Gln at position 8 | Yes | No |
| Ala at position 15 | Yes | No |
| Leu at position 27 | Yes | No |
| C-terminal amide | Yes | Yes |
| Average molecular weight | ~3,367.9 g/mol | ~3,357.9 g/mol |
| Molecular formula | C₁₅₂H₂₅₂N₄₄O₄₂ | C₁₄₉H₂₄₆N₄₄O₄₂S |
Although the molecular weights are relatively close, the peptides have different amino acid compositions and stereochemical characteristics.
This is why their names and analytical profiles should not be treated as interchangeable.
7. Chemical Characteristics Relevant to Laboratory Analysis
Modified GRF (1-29) contains a variety of polar, charged, and hydrophobic amino acid residues.
These influence molecular interactions and analytical behavior.
Charge Distribution
The peptide contains basic residues, including arginine and lysine.
It also contains acidic residues, including aspartic acid.
Their protonation states influence the molecule’s net charge.
The resulting charge distribution depends on the pH of the environment.
Solubility
The peptide has several polar functional groups.
Nevertheless, solubility depends on the actual material form, solvent conditions, ionic strength, concentration, and temperature.
A universal solubility specification should not be assigned without supporting experimental data.
Surface Adsorption
Peptides may interact with laboratory surfaces through electrostatic and hydrophobic interactions.
Surface adsorption can affect sample recovery and measured concentration.
This should be considered when interpreting analytical results involving low-concentration samples.
Molecular Association
A peptide’s physicochemical environment can influence its association with other molecules.
Aggregation or other forms of molecular association may not always produce visible changes.
A clear appearance does not independently confirm chemical purity or molecular homogeneity.
8. Analytical Characterization of Modified GRF (1-29)
Laboratory characterization should establish the identity of the peptide under investigation.
For CJC-1295 No DAC, this includes confirmation that the material corresponds to the 29-residue structure and does not contain the DAC chemical modification.
Reversed-Phase HPLC
Reversed-phase high-performance liquid chromatography separates components according to their chromatographic interactions.
It can provide information about peptide-related impurities and the principal compound peak.
However, chromatographic purity is method-dependent.
A high peak-area purity result does not necessarily establish absolute peptide content.
Electrospray Mass Spectrometry
Electrospray ionization mass spectrometry can generate multiply charged peptide ions.
The resulting signals can be used to estimate the intact molecular mass.
For Modified GRF (1-29), the expected average molecular weight is approximately 3,367.9 g/mol.
LC-MS/MS
Liquid chromatography-tandem mass spectrometry combines separation with fragmentation analysis.
It can provide additional information about peptide sequence and certain modified structures.
For a peptide containing a D-amino acid, appropriate stereochemical verification may also be needed if the analytical objective requires confirmation of the D-configuration.
Distinguishing DAC and No DAC in MS
A molecular mass near 3,368 Da supports the non-DAC reference structure.
A mass near 3,647 Da is consistent with the unconjugated DAC-containing construct.
These values should be interpreted according to charge states, isotope conventions, and the actual chemical forms present.
An analytical report should not identify a compound solely from its commercial name.
9. Understanding a CJC-1295 No DAC Certificate of Analysis
A Certificate of Analysis documents specified tests performed on an identified batch.
For Modified GRF (1-29), relevant documentation includes the peptide’s sequence-related identity and chromatographic characteristics.
| COA component | What it establishes |
|---|---|
| Exact compound designation | Whether the reference is Modified GRF (1-29) |
| Peptide sequence | Intended 29-residue structure |
| Molecular formula | Reference elemental composition |
| Expected molecular mass | Theoretical MS comparison |
| Batch number | Material traceability |
| HPLC chromatogram | Separation profile |
| HPLC purity | Chromatographic result under defined conditions |
| Mass spectrometry | Molecular mass-related evidence |
| Peptide content | Quantity when separately measured |
| Counterion content | Associated ions where tested |
| Water content | Moisture where measured |
| Analytical method | Testing procedure |
| Testing date | When the analysis was performed |
Can HPLC Alone Distinguish CJC-1295 with and without DAC?
A suitable chromatographic method may separate them.
However, chromatographic retention alone is not definitive structural identification.
Mass spectrometry and other appropriate tests provide complementary evidence.
What Does 99% HPLC Purity Mean?
It generally describes the relative chromatographic response attributed to the principal component under a specified method.
It does not necessarily indicate that 99% of the entire material mass consists of the peptide.
Why Is a Batch-Matched COA Important?
Peptide synthesis and purification can produce different impurity profiles between batches.
A batch-specific report provides a traceable connection between analytical findings and the actual material tested.
10. Stability Questions Specific to Modified GRF (1-29)
Peptide stability is influenced by amino acid sequence, terminal modifications, chemical form, and surrounding conditions.
Modified GRF (1-29) contains several substitutions intended to alter susceptibility to particular degradation processes.
However, chemical modification does not eliminate every possible degradation pathway.
D-Alanine and Enzymatic Stability
The D-alanine substitution at position 2 is associated with reduced susceptibility to certain N-terminal proteolytic processes.
This is distinct from overall chemical stability during storage.
Methionine Replacement
The leucine substitution at position 27 removes methionine’s sulfur-containing thioether.
Therefore, the modified peptide lacks the methionine oxidation site present in natural GHRH (1-29).
Other residues and chemical groups may still undergo changes.
Asparagine Replacement
Replacing asparagine with glutamine changes the side-chain amide structure.
It also changes the molecule’s susceptibility to reactions associated with that particular residue.
However, glutamine and other groups may still undergo chemical changes under suitable conditions.
Lyophilized Material and Solutions
The stability of a dry material can differ from its stability in solution.
Factors such as residual moisture, pH, temperature, and formulation composition may influence degradation.
A specific shelf-life claim requires evidence for the exact material under defined conditions.
11. Technical Questions About CJC-1295 No DAC
What is CJC-1295 No DAC?
It is the common name for Modified GRF (1-29), a synthetic 29-residue GHRH analog without a Drug Affinity Complex.
What is another name for CJC-1295 No DAC?
Modified GRF (1-29) or Mod GRF 1-29.
How many amino acids does it contain?
29 residues.
What is the molecular formula?
C₁₅₂H₂₅₂N₄₄O₄₂.
What is its molecular weight?
Approximately 3,367.9 g/mol.
What is the commonly assigned CAS number?
863288-34-0.
What is the PubChem CID?
56841945 for the modified 29-residue peptide structure.
What does DAC mean?
Drug Affinity Complex.
Does the No DAC peptide contain a maleimide group?
No.
Does CJC-1295 No DAC contain a C-terminal amide?
Yes.
Is the peptide cyclic?
No. It has a linear peptide backbone.
Does it contain disulfide bonds?
No. Its reference sequence contains no cysteine residues.
What are its four substitutions?
D-Ala at position 2, Gln at position 8, Ala at position 15, and Leu at position 27.
Why is D-alanine important?
It changes the stereochemistry of the second residue and can influence enzymatic recognition.
Is CJC-1295 No DAC the same as Sermorelin?
No. Both contain 29 residues, but their sequences and chemical compositions differ.
Is CJC-1295 No DAC the same as CJC-1295 with DAC?
No. The DAC-containing molecule has an additional chemically modified lysine residue.
Can mass spectrometry distinguish the two forms?
Yes, appropriate MS methods can distinguish their different molecular masses.
What does HPLC purity establish?
It reports chromatographic purity under the specified test conditions.
Does an HPLC result confirm stereochemistry?
Not automatically.
Can CJC-1295 No DAC undergo degradation?
Yes. Its stability depends on its chemical structure and experimental environment.
Is CJC-1295 No DAC FDA-approved?
No. Modified GRF (1-29) is not an FDA-approved drug substance.
12. Scientific References and Chemical Resources
Original DAC-Containing CJC-1295 Molecular Development
Jetté L. et al. (2005)
Human Growth Hormone-Releasing Factor (hGRF)1-29-Albumin Bioconjugates Activate the GRF Receptor on the Anterior Pituitary in Rats: Identification of CJC-1295 as a Long-Lasting GRF Analog.
Journal: Endocrinology.
Technical relevance: Modified GRF sequence design, maleimide chemistry, covalent albumin conjugation, and the distinction between the DAC-containing construct and its peptide backbone.
https://doi.org/10.1210/en.2004-1286
Important: This publication characterizes the DAC-containing CJC-1295 construct. Its findings must not be presented as direct pharmacological or stability data for the independently supplied No DAC peptide.
Modified GRF (1-29) Chemical Reference
PubChem CID 56841945
Technical relevance: Chemical structure, molecular formula, mass, amino acid modifications, and identifiers.
https://pubchem.ncbi.nlm.nih.gov/compound/56841945
DAC-Containing CJC-1295 Chemical Reference
PubChem CID 91971820
Technical relevance: The larger DAC-containing structure and its molecular identifiers.
https://pubchem.ncbi.nlm.nih.gov/compound/91971820
Peptide Characterization and Structural Identification
Henninge J. et al. (2010)
CJC-1295: A Growth Hormone-Releasing Hormone Analogue Identified in a Pharmaceutical Preparation.
Journal: Drug Testing and Analysis.
Technical relevance: Analytical characterization of a peptide marketed as CJC-1295.
https://pubmed.ncbi.nlm.nih.gov/21204297
Peptide Analytical Methodology
Memdouh S. et al. (2021)
Detection and Characterization of Growth Hormone-Releasing Hormone Analogues and Their Metabolites.
Research relevance: Chromatography, mass spectrometry, peptide-related metabolites, and differentiation of molecular forms.
Conclusion
CJC-1295 No DAC is the commonly used name for Modified GRF (1-29), a synthetic 29-amino-acid analog of GHRH.
Its identity is defined by four amino acid substitutions, a C-terminal amide, and the absence of the albumin-reactive Drug Affinity Complex.
These structural features distinguish it from natural GHRH (1-29), Sermorelin, and DAC-containing CJC-1295.
From an analytical standpoint, the distinction between DAC and No DAC is especially important because the molecules have different formulas, masses, and chemical properties.
Laboratory characterization should establish the actual sequence-related identity and distinguish theoretical molecular properties from batch-specific results.
Accurate documentation requires clear compound naming, suitable mass spectrometry, chromatographic characterization, and traceable Certificates of Analysis.
Technical research notice: This article covers molecular chemistry, structural identity, receptor-related laboratory research, and analytical characterization. It does not include dosing, administration, reconstitution, or personal-use instructions. CJC-1295 No DAC is not FDA-approved, and analytical results do not establish the suitability of independently supplied research material for human or veterinary use.
