GRF(1-29) comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-04-03. Numbers and descriptions here follow the published literature rather than marketing material.
Identity and purity are established with reversed phase high performance liquid chromatography coupled to mass spectrometry. The chromatographic step separates the target peptide from truncated sequences and deletion products, while the mass measurement confirms the expected molecular weight to within a fraction of a dalton. Because the two common variants differ by the presence of the linker, mass alone can distinguish them in the unconjugated state. Amino acid analysis and peptide mapping are used when sequence level confirmation is required.
Lyophilized material is generally stable for extended periods when held at minus twenty degrees Celsius or below and protected from moisture and light. In solution the peptide is more labile; bond hydrolysis, aggregation and oxidation of susceptible residues all proceed faster at ambient temperature. Repeated freeze and thaw cycles should be avoided because they promote clumping and loss of soluble material. The conjugated variant adds a further consideration, since the maleimide group can hydrolyze in aqueous buffer and lose its ability to react with albumin.
Reverse-phase high-performance liquid chromatography is the standard tool for purity assessment. The technique separates the target peptide from truncated or modified byproducts. Mass spectrometry confirms molecular weight and supports sequence verification. Electrospray ionization and matrix-assisted laser desorption are both used. Amino acid analysis provides an independent check on composition. Purity values are commonly reported as area percentage from the chromatogram. Residual trifluoroacetate and water content are also measured in many quality programs.
Batch-to-batch consistency depends on solid-phase peptide synthesis and subsequent purification. Coupling efficiency, resin choice, and cleavage conditions all affect the final profile. Counter-ion content and moisture can shift the apparent mass of a batch. Documentation typically includes a certificate of analysis with chromatograms and spectra. Independent verification by a second laboratory is sometimes requested. Whether a given certificate reflects the actual vial contents depends on chain of custody. Analytical methods themselves carry uncertainty that should be stated alongside results.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off white powder | Typical lyophilized form |
| Water solubility | Soluble | May need a small organic co-solvent |
| Purity assessment | Chromatographic peak area | Most certificates report a percentage figure |
| Storage temperature | Minus 20 C or lower | Dry, dark, sealed container |
| Identity check | Electrospray mass spectrometry | Compared against theoretical mass |
CJC-1295 is a synthetic peptide analog of growth hormone-releasing hormone, constructed on the 29-amino-acid fragment designated GRF(1-29). The name began as an internal development code during the 1990s and later spread through research supply catalogs and discussion forums. The molecule does not occur in nature; its sequence is engineered rather than isolated from tissue. Two related compounds are sold under this single label, and they differ by one appended chemical group that strongly influences how long the peptide remains in circulation.
The dividing feature between the two forms is a maleimide-based drug affinity complex, abbreviated DAC. In the DAC-bearing version, a linker attaches the peptide to serum albumin after administration, and that association slows removal from plasma. The version lacking DAC appears in catalogs as MOD GRF(1-29) or tetrasubstituted GRF(1-29). Because informal writing treats both as one item, comparisons drawn from such sources routinely blend measurements taken from two molecules with substantially different behavior.
Four amino acid substitutions separate the modified backbone from the parent GRF(1-29) sequence. These changes reduce recognition by dipeptidyl peptidase IV and related proteases, extending the interval before degradation. Development work in this area sought longer-acting GHRH analogs for endocrine investigation. Published descriptions treat the substitution set as a defining property of the core sequence, while the albumin-binding linker is described separately as an optional addition to that same backbone.
CJC-1295 is a synthetic peptide built as a long-acting analogue of growth hormone-releasing hormone. Its backbone matches the first twenty-nine residues of the natural human hormone, with four amino acid substitutions added to slow enzymatic breakdown. A reactive maleimide group, commonly termed the drug affinity complex, allows the peptide to attach to circulating albumin after administration. That albumin attachment keeps the molecule in the bloodstream for an extended period instead of being cleared within minutes.
The compound emerged from work at a Canadian biotechnology firm in the early 2000s. Early human studies examined its effect on growth hormone and insulin-like growth factor 1 in healthy volunteers and in people with HIV-associated fat redistribution. Reports described sustained increases in both markers after a single injection. Development did not advance to regulatory approval, and the clinical programme was later discontinued. The molecule is now encountered mainly as a research chemical rather than a marketed medicine.
Two forms circulate in research settings and are frequently confused. One carries the drug affinity complex and is often written as CJC-1295 with DAC; the other lacks that group and is usually called modified GRF(1-29). The two share the same core sequence but differ sharply in how long they persist in blood. Products labelled only as CJC-1295 normally refer to the version carrying the complex. Documentation that omits the distinction leaves the intended molecule ambiguous.
== Description == The neon tetra has a light-blue back over a silver-white abdomen. The fish is characterized by a bright iridescent blue horizontal stripe along each side of the fish from its nose to the base of the adipose fin, and an iridescent red stripe that begins at the middle of the body and extends posteriorly to the base of the caudal fin. The fish is partially transparent (including fins) except for these markings. Sexual dimorphism is slight, with the female having a slightly larger belly, and a bent iridescent stripe rather than the male's straight stripe. During the night, the blue and red become gray or black as the fish rests. It reactivates once it becomes active in the morning. This peculiar change is due to the neon tetras capacity to change the color of its iridescent stripe in response to lighting conditions. In a light-adapted state it is blue-green, likewise in a dark-adapted state its color changes to indigo. This change is produced by guanine crystals in their cells that reflect light. The neon tetra grows to approximately 4 cm (1.6 in) in overall length.
He will be strong enough to get up and two days later he leaves the home.However, even in 1934 he was suspicious of the idea that the treatment was pure conditioned reflex – "though vomiting is one of the ways that apomorphine relives the patient, I do not believe it to be its main therapeutic effect." – and by 1948 he wrote:It is now twenty-five years since I began treating cases of anxiety and alcoholism with apomorphine, and I read my first paper before this Society fourteen years ago. Up till then I had thought, and, unfortunately, I said in my paper, that the virtue of the treatment lay in the conditioned reflex of aversion produced in the patient. This statement is not even a half truth… I have been forced to the conclusion that apomorphine has some further action than the production of a vomit.This led to his development of lower-dose and non-aversive methods, which would inspire a positive trial of his method in Switzerland by Dr Harry Feldmann.
Interestingly, the full-length CUX1 protein purified from insect cells exhibited DNA binding kinetics similar to that of CR1CR2, suggesting that the Cut homeodomain may not be active in the context of the full-length protein.
Rush's popularity reached its pinnacle with the release of Moving Pictures in February 1981. Essentially, Moving Pictures continued where Permanent Waves left off, extending the trend of accessible and commercially friendly progressive rock which helped thrust them into the spotlight. The lead track, "Tom Sawyer", is probably the band's best-known song. When it was released, it reached No. 24 on the Canadian Top 40 Singles Chart, No. 44 on the Billboard Hot 100, and No. 8 on the new US Album Rock Tracks chart. The second single, "Limelight", also received a strong response from listeners and radio stations, going to No. 18 in Canada, No. 54 on the Hot 100, and No. 4 on the US Album Rock Tracks Chart. Moving Pictures was Rush's last album to feature an extended song, the 11-minute "The Camera Eye". The song contained the band's heaviest usage of synthesizers yet, hinting that Rush's music was shifting direction once more. Moving Pictures became the band's first album to reach No. 1 on the Canadian Albums Chart, and also reached No. 3 on the US Billboard 200 and UK album charts; it has been certified quintuple platinum by both the Recording Industry Association of America and Music Canada. After the success of Moving Pictures, Rush released their second live recording, Exit... Stage Left, in 1981.
Sources: en.wikipedia.org
Selenium has seven naturally occurring isotopes. Five of these, 74Se, 76Se, 77Se, 78Se, 80Se, are stable, with 80Se being the most abundant (49.6% natural abundance). Also naturally occurring is the long-lived primordial radionuclide 82Se, with a half-life of 8.76 × 1019 years. The non-primordial radioisotope 79Se also occurs in minute quantities in uranium ores as a product of nuclear fission. Selenium also has numerous unstable synthetic isotopes ranging from 64Se to 95Se; the most stable are 75Se with a half-life of 119.78 days and 72Se with a half-life of 8.4 days. Isotopes lighter than the stable isotopes primarily undergo beta plus decay to isotopes of arsenic, and isotopes heavier than the stable isotopes undergo beta minus decay to isotopes of bromine, with some minor neutron emission branches in the heaviest known isotopes.
Substitution of the poly-Pro II (φ,ψ) dihedral angles into this equation yields almost exactly Ω = -120°, i.e., the PPII helix is a left-handed helix (since Ω is negative) with three residues per turn (360°/120° = 3). The rise per residue is approximately 3.1 Å. This structure is somewhat similar to that adopted in the fibrous protein collagen, which is composed mainly of proline, hydroxyproline, and glycine. PPII helices are specifically bound by SH3 domains; this binding is important for many protein-protein interactions and even for interactions between the domains of a single protein. The PPII helix is relatively open and has no internal hydrogen bonding, as opposed to the more common helical secondary structures, the alpha helix and its relatives the 310 helix and the pi helix, as well as the β-helix. The amide nitrogen and oxygen atoms are too far apart (approximately 3.8 Å) and oriented incorrectly for hydrogen bonding. Moreover, these atoms are both H-bond acceptors in proline; there is no H-bond donor due to the cyclic side chain. The PPII backbone dihedral angles (-75°, 150°) are observed frequently in proteins, even for amino acids other than proline. The Ramachandran plot is highly populated in the PPII region, comparably to the beta sheet region around (-135°, 135°). For example, the PPII backbone dihedral angles are often observed in turns, most commonly in the first residue of a type II β-turn. The "mirror image" PPII backbone dihedral angles (75°, -150°) are rarely seen, except in polymers of the achiral amino acid glycine.
=== "Last dictators" advertisement === In 2011, Nando's launched a "Last dictators" advert in South Africa. The 60-second commercial shows a sad Robert Mugabe dining alone at Christmas in a large mansion while he reminisces about "happier times" with former dictators, such as playing water tag with Muammar Gaddafi, singing karaoke with Mao Zedong, making snow angels in the sand with Saddam Hussein, pushing P. W. Botha on a swing set, and riding a Covenanter cruiser tank with Idi Amin in a similar fashion to Leonardo DiCaprio and Kate Winslet embracing each other from the film Titanic, while the music from "Those Were the Days" is played. Musekiwa Kumbula, holder of the Nando's franchise in Zimbabwe, said his group "strongly feels the advertisement is insensitive and in poor taste." The advert also offended Chipangano, a Zimbabwean youth militia loyal to Mugabe, who then demanded an apology from Nando's, threatened to boycott the South Africa-based chain, and demanded the advert be withdrawn or the restaurant face retribution. Nando's South Africa subsequently withdrew the advert citing threats to its staff in Zimbabwe from a youth group.
Sources: en.wikipedia.org
The mass difference from the linker is large enough for routine detection by mass spectrometry. The unconjugated form gives a single sharp signal at its expected weight. Material that has already reacted with albumin shows a much higher mass and a broadened chromatographic peak.
Yes. Degradation proceeds faster once the powder is dissolved, especially at room temperature or after multiple freeze and thaw cycles. Working solutions are often aliquoted to avoid repeated handling. Lyophilized powder held cold and dry retains its properties far longer.
Truncated sequences, oxidized residues and aggregated forms can all elute near the main peak. Reversed phase chromatography resolves many of these species, so the number of peaks is a useful indicator of synthesis quality. A single peak does not by itself prove correct sequence, which is why mass confirmation is paired with it.
The powder is normally held at minus twenty degrees Celsius or below. Light and moisture exposure should be minimized. Repeated warming and cooling cycles are avoided.