This is a working overview of mass spectrometry, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-14 and is reviewed periodically as new material appears.
Two related forms appear under the CJC-1295 name. The simpler analogue, commonly written as modified GRF(1-29), carries the four substitutions but no additional conjugation. The second form attaches a maleimidopropionic acid linker to a lysine residue, a modification frequently called the drug affinity complex. That linker reacts with the free thiol on serum albumin to form a covalent bond. Because albumin has a long residence time in blood, the conjugated peptide stays in circulation far longer than the unconjugated analogue.
Receptor level activity follows the canonical GHRH pathway. The peptide binds the GHRH receptor, a class B G protein coupled receptor on somatotroph cells of the anterior pituitary. Binding raises intracellular cyclic AMP, which promotes calcium entry and the release of growth hormone into the bloodstream. Because the molecule acts at the same receptor as the endogenous hormone, its effect is superimposed on the natural pulsatile rhythm rather than replacing it. Whether sustained receptor occupation leads to desensitization is not fully settled.
Lyophilised powder is the usual supplied form. The material is hygroscopic, so vials are typically equilibrated to room temperature before opening in order to prevent condensation on the contents. Long-term storage is generally described at minus twenty degrees Celsius or colder, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of soluble material. A reconstituted solution is considerably less stable than the dry powder and is normally kept refrigerated for short periods only.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography combined with mass spectrometry. The chromatographic separation resolves the target peptide from truncation products and from species carrying oxidised residues, while mass measurement confirms the expected molecular mass. Because the two common variants differ by roughly 280 daltons, a mass determination distinguishes them unambiguously. Purity is often quoted as a percentage of total peak area, although that figure depends on the detection wavelength and the integration method applied.
| Property | Value | Notes |
|---|---|---|
| Peptide class | Synthetic GHRH analogue | Built on a 29 residue sequence |
| Primary target | GHRH receptor (GHRHR) | Class B G protein coupled receptor |
| Unconjugated half life | Minutes | Limited by protease degradation |
| Key modification | Four residue substitutions | Positions 2, 8, 15 and 27 |
| Common synonym | Modified GRF(1-29) | Usually denotes the form without DAC |
In most of the syntheses described here, it is necessary to attach and remove the starting reagent to/from a solid support. This can lead to the generation of a hydroxyl group, which can potentially affect the biological activity of a target compound. Ellman uses solid phase supports in a multi-step synthesis scheme to obtain 192 individual 1,4-benzodiazepine derivatives, which are well-known therapeutic agents. To eliminate the possibility of potential hydroxyl group interference, a novel method using silyl-aryl chemistry is used to link the molecules to the solid support which cleaves from the support and leaves no trace of the linker.
Stanley, who suggested that the arms were used for slashing prey, especially by using the claws to rapidly inflict long, deep gashes to its prey. This was dismissed by Padian, who argued that Stanley based his conclusion on incorrectly estimated forelimb size and range of motion.
While the review in the JB&JS was able to correlate receiving rodding surgery with greater mobility across all types of OI, in patients with type IV, the surgery did not decrease the incidence of broken bones as compared to non-rodded patients—while type IV patients with rodded tibiae experienced 0.93 tibia fractures per year, patients with natural tibiae experienced only 0.81. However, in patients with type III, rodding surgery decreased the average number of tibia fractures per year from 0.84 to 0.57.
Sources: en.wikipedia.org
codons, resulting in 2078 free parameters. However, the rates for transitions between codons which differ by more than one base are often assumed to be zero, reducing the number of free parameters to only
To the east and north of the rebuilt central city are a stretch of old neighbourhoods (Danton, Saint-Vincent, Graville, Massillon, etc.) which were spared the bombings of World War II. The buildings, usually in brick, dated to the 19th and the first half of the 20th centuries. The shops are concentrated along several major roads in the Rond-Point neighbourhood. During the 1990s and 2000s, these neighborhoods have seen major redevelopments, particularly in the context of an OPAH: improvement of habitat by rehabilitation or reconstruction, creation of public facilities, and revitalization of business. At the end of the 20th century and beginning of the 21st century, the area around the railway station has undergone a major transformation. As the station is the gateway to the city with the main avenues intersecting here. New buildings have sprung up (University of Le Havre, the conservatory, headquarters of the SPB (Provident Society Bank), and of CMA CGM, Novotel, Matmut, new CCI) some of which were designed by renowned architects. The bus station, certified NF since 2005, has been refurbished. North of the station, another construction project in place of the dilapidated island of Turgot-Magellan will be opened in 2013, including 12,500 m2 (135,000 sq ft) of office space and an eight-storey hotel, complete with shops on the ground-floor.
Verucerfont (GSK-561,679) is a drug developed by GlaxoSmithKline which acts as a CRF-1 antagonist. Corticotropin releasing factor (CRF), also known as Corticotropin releasing hormone, is an endogenous peptide hormone which is released in response to various triggers such as chronic stress, and activates the two corticotropin-releasing hormone receptors CRH-1 and CRH-2. This then triggers the release of corticotropin (ACTH), another hormone which is involved in the physiological response to stress. Verucerfont blocks the CRH-1 receptor, and so reduces ACTH release following chronic stress. It is under investigation as a potential treatment for alcoholism, as chronic stress is often a factor in both development of alcoholism and relapse in recovering alcoholics. It has shown promising results in animal studies. However, human trials have shown that while the neuroendocrine effects translate from animal models, the alcohol anti-craving effects do not.
Sources: en.wikipedia.org
The names are often used interchangeably in casual writing, but they are not strictly identical. Modified GRF(1-29) refers to the unconjugated analogue carrying only the four substitutions. The version sold as CJC-1295 with DAC includes the albumin binding linker and clears much more slowly.
DAC stands for drug affinity complex, a term describing the maleimidopropionic acid linker. This group forms a covalent bond with the cysteine residue on serum albumin after administration. The resulting adduct is what extends the circulating half life from minutes to days.
No. It is entirely synthetic and does not correspond to any known endogenous peptide. The design starts from human growth hormone releasing hormone and introduces deliberate substitutions. Any biological effect comes from mimicking the natural hormone at its receptor.
Chromatography reports how much material elutes as a single peak but does not confirm what that material is. Mass spectrometry supplies the molecular mass, which is characteristic of a given sequence and its modifications. Together the two methods support both a purity figure and an identity claim.