CJC-1295 exists in two chemically different variants that are traded under the same name. The distinction is a standard case for mass spectrometric identity testing.
What is CJC-1295?
CJC-1295 is derived from growth hormone-releasing hormone, more precisely from the fragment GRF(1-29). Compared with the natural sequence, four amino acid positions are exchanged, which makes the compound more stable against enzymatic degradation.
- CJC-1295 without DAC, also designated Modified GRF(1-29), comprises 29 amino acids with a molecular mass of approximately 3,368 Da.
- CJC-1295 with DAC additionally carries a drug affinity complex group, a maleimidopropionyl linker on an additional lysine. The molecular mass is therefore approximately 3,647 Da.
The mass difference of around 280 Da is clear and makes the two variants unambiguously distinguishable analytically.
Research context
Both variants are described in the literature on growth hormone secretagogues. An approved medicinal product does not exist. For comparison purposes it is decisive which of the two variants is actually present in an experiment or in a batch, since the molecules differ in mass, hydrophobicity and chromatographic behaviour. Statements about one variant cannot be transferred to the other.
Analytical identification
- LC-MS is the method of choice here. Peptides of this size produce a multiply charged ion series in positive electrospray, from which the mass is determined by deconvolution. The difference between approximately 3,368 Da and approximately 3,647 Da can thereby be assigned beyond doubt.
- RP-HPLC on C18 phases with a water/acetonitrile gradient likewise separates the two variants, since the DAC linker increases hydrophobicity and lengthens the retention time. Without a reference standard, however, the retention time alone does not permit identification.
A data sheet that merely names CJC-1295 and states a purity value does not clarify the variant question. Only a mass figure or a written-out designation with or without DAC makes the document unambiguous.
Purity and analytical interpretation
At 29 to 30 amino acids, typical synthesis impurities such as deletion sequences occur that lie chromatographically close to the target peptide. A high area-percent value does not reliably exclude such by-products. With the DAC variant there is the additional point that incomplete conjugation can lead to a mixture of conjugated and non-conjugated peptide, which only becomes visible in the UV chromatogram if the separation is sufficient.
Documentation and batch traceability
Robust documentation names the variant, the measured mass, the method and the batch reference. If one of these details is missing, assigning a document to a specific sample is not possible.
Storage and Stability
Lyophilised material is to be stored dry, protected from light and refrigerated; for longer laboratory stocks minus 20 degrees Celsius is usual. Repeated freeze-thaw cycles are to be avoided. These details concern exclusively the handling of laboratory substances.
Further research resources
- LC-MS in peptide analysis
- HPLC vs. LC-MS: differences in peptide analysis
- Batch testing and traceability
- Analysis and certificates
Associated catalogue products
This page serves exclusively as scientific and analytical information. It contains no dosage, application or treatment instructions. Products are not intended for use in humans or animals.