DAC group is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-11-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
Peptide degradation proceeds mainly through hydrolysis, oxidation of methionine, and deamidation of asparagine or glutamine residues. The maleimide group on the albumin-binding variant can also react with thiols or hydrolyze in aqueous media. Because these pathways accelerate with temperature and pH extremes, handling conditions strongly influence measured stability. Stability data in the public literature are limited and often generated under differing conditions, so general statements about shelf life should be read as approximate.
Research material is normally supplied as a freeze-dried powder in sealed vials. In that state the peptide is comparatively robust, but prolonged exposure to warmth, moisture, or light accelerates degradation. Storage at minus twenty degrees Celsius or lower, with desiccant and protection from light, is the commonly described practice. Vials should be allowed to reach room temperature before opening to limit condensation on the powder. Moisture uptake during handling is a recognized source of variability in later measurements.
Reconstitution is typically performed with sterile water or bacteriostatic water, added slowly against the vial wall. The resulting solution should be clear and colorless; cloudiness or visible particles suggest a problem with the material or the diluent. Once in solution, the peptide is less stable than the dry powder. Refrigerated storage at two to eight degrees Celsius is common for short-term holding, while freezing aliquots is described for longer periods.
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 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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white lyophilized powder | Visual descriptor; not a measure of purity |
| Solubility class | Freely soluble in water | Aqueous dissolution may require gentle mixing |
| Typical storage (powder) | −20 °C or below, desiccated | Protect from light and ambient moisture |
| Typical storage (solution) | 2–8 °C, short term | Freeze aliquots where longer holding is needed |
| Purity assessment | Reversed-phase HPLC, area percent | Values depend on column, gradient, and detection wavelength |
CJC-1295 is the name used for a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. The compound was described by a Canadian drug discovery company in the mid-2000s as a long-acting research tool. Two closely related molecules share the name in practice: one carries a drug affinity complex, or DAC, group, and one does not. The distinction matters because the two behave differently in circulation.
The peptide backbone corresponds to GRF(1-29), the first 29 residues of native growth hormone-releasing hormone, which retains most of the receptor-activating activity of the full-length molecule. Four substitutions distinguish the analog from the natural sequence: D-alanine at position 2, glutamine at position 8, alanine at position 15, and leucine at position 27. These changes slow cleavage by dipeptidyl peptidase IV, the enzyme that degrades native hormone in plasma within minutes. The outcome is improved enzymatic stability combined with a still brief residence time when no additional modification is present.
Naming in this area is inconsistent, and readers should treat product labels with care. In much of the literature and in vendor catalogs, the unqualified term refers to the albumin-binding version, while the version lacking the DAC group appears as modified GRF(1-29), mod GRF(1-29), or the same name with a without-DAC qualifier. Because one abbreviation has been applied to both materials, the only reliable way to identify a sample is to check the stated sequence and the presence of the linker.
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.
Laboratory handling centers on minimizing exposure to water, heat and oxygen before use. Working solutions are typically prepared in sterile water or a mild buffer, and any residual particulate matter is removed by filtration. When the powder dissolves slowly, a small proportion of acetonitrile or dilute acetic acid is sometimes added as a co-solvent. Containers are kept sealed and desiccated between uses. Records of lot number, reconstitution date and storage conditions support later comparison of results across experiments.
Duke Nukem Forever had been a project with a troubled development history at 3D Realms, who had created the Duke Nukem series, since sometime prior to 2000. Due to financial difficulties in 2009, 3D Realms was forced to downsize and ultimately lay off most of the development staff. Take-Two Interactive sued 3D Realms for failing to deliver Duke Nukem Forever. Pitchford, who had prior industry relations with many 3D Realms staff including George Broussard, learned that many of the 3D Realms team were still eager to develop Duke Nukem Forever, working out of their homes on what they could. Pitchford negotiated with Take-Two to bring many of the former 3D Realms staff into a new studio called Triptych Games, housed at Gearbox's headquarters, to continue working on Duke Nukem Forever following 3D Realms' closure in 2009. As a result, 3D Realms sold the rights to Duke Nukem and the existing work on Duke Nukem Forever to Gearbox around February 2010. Take-Two and Gearbox subsequently announced in September 2010 that Gearbox would finish production of Duke Nukem Forever. Duke Nukem Forever was released in June 2011, and received negative critical reception on release, with most of the criticism directed towards the unfinished, rushed state of the game. Despite the criticism, the game topped the charts on release and made a profit. 3D Realms had initially sued Gearbox in June 2013 for unpaid royalties over Duke Nukem Forever, but dropped the suit by September 2013, with 3D Realms' founder Scott Miller stating that it was a misunderstanding on its part.
Teleost leptins are a family of peptide hormones found in fish (teleostei) that are orthologs of the mammalian hormone leptin. The teleost and mammalian leptins appear to have similar functions, namely, regulation of energy intake and expenditure. The leptin (LEP) hormone was long thought to be specific to mammals, but in recent years the gene (lep) has been found in amphibia such as the tiger salamander (Ambystoma tigrinum), and the African clawed frog (Xenopus laevi). The discovery of lep in puffer fish (Takifugu rubripes) demonstrates the ancient ancestry of this hormone.
In the United States domestic market, the chain fell to third place in terms of same-store sales behind Ohio-based Wendy's. The decline was the result of 11 consecutive quarters of same store sales decline. In August 2014, 3G announced that it planned to acquire the Canadian restaurant and coffee shop chain Tim Hortons and merge it with Burger King with backing from Warren Buffett's Berkshire Hathaway. The two chains retained separate operations post-merger, with Burger King remaining in its Miami headquarters. A Tim Hortons representative stated that the proposed merger would allow Tim Hortons to leverage Burger King's resources for international growth. The combined company became the third-largest international chain of fast food restaurants. The deal led to a controversy over the practice of tax inversions, in which a company decreases the amount of taxes it pays by moving its headquarters to a tax haven, a country with lower rates, but maintains the majority of their operations in their previous location. As a high-profile instance of tax inversion, news of the merger was criticized by U.S. politicians, who felt that the move would result in a loss of tax revenue to foreign interests, and could result in further government pressure against inversions. In 2019, Burger King reported that it planned to close up to 250 low-volume locations per year, with closures coming into effect in 2020. In February 2021, Burger King began testing a customer loyalty rewards program called "Royal Perks" in Los Angeles, Miami, New York City, New Jersey, and Long Island, New York.
The Kennedy pathway, which includes the transformation of choline to citicoline, by way of phosphorylcholine, produces phosphatidylcholine when condensed with diacylglycerol. Phosphatidylcholine can also be produced by the methylation pathway, where phosphatidylethanolamine is sequentially methylated.
Sources: en.wikipedia.org
== History == The natriuretic effects of progesterone were demonstrated in 1955, and the development of spironolactone as a synthetic antimineralocorticoid analogue of progesterone shortly followed this. Spironolactone was first synthesized in 1957, was patented between 1958 and 1961, and was first marketed, as an antimineralocorticoid, in 1959. Gynecomastia was first reported with spironolactone in 1962, and the antiandrogenic activity of the medication was first described in 1969. This shortly followed the discovery in 1967 that gynecomastia is an important and major side effect of AR antagonists. Spironolactone was first studied in the treatment of hirsutism in women in 1978. It has since become the most widely used antiandrogen for dermatological indications in women in the United States. Spironolactone was first studied as an antiandrogen in transgender women in 1986, and has since become widely adopted for this purpose as well, particularly in the United States where cyproterone acetate is not available. Early oral spironolactone tablets showed poor absorption. The formulation was eventually changed to a micronized formulation with particle sizes of less than 50 μg, which resulted in approximately 4-fold increased potency.
He also said that the government would also target 86 more people and companies connected to President Putin, including people who were "actively undermining the impact of existing sanctions". Sunak said that the new sanctions were made to ensure Russia paid "a price for its illegal activity" and urged other G7 countries to follow suit. The United States also announced that it would tighten export controls to Russia, particularly with regard to militarily important goods, and impose nearly 300 new sanctions against targets linked to Russia. Canada also imposed sanctions on targets linked to the Russian military, relatives of listed persons, members of the Kremlin elite, and those involved in human rights violations. In response to these sanctions, the Russian Foreign Ministry announced a ban on entry into the country on 500 Americans including former President Barack Obama, comedians Stephen Colbert, Jimmy Kimmel and Seth Meyers, Senators JD Vance, Katie Britt and Eric Schmitt, former US Ambassador Jon Huntsman Jr., presumptive Chairman of the Joint Chiefs of Staff General Charles Q. Brown Jr. and several journalists of CNN. Also included were officials involved in the prosecution of participants in the United States Capitol attack in 2021. It also continued to deny US consular access to detained journalist Evan Gershkovich in retaliation for the blocking of entry to Russian journalists during Foreign Minister Sergei Lavrov's visit to the UN in New York in April 2023.
==== Three-dimensional structure ==== The three-dimensional structure of heparin is complicated because iduronic acid may be present in either of two low-energy conformations when internally positioned within an oligosaccharide. The conformational equilibrium is influenced by the sulfation state of adjacent glucosamine sugars. Nevertheless, the solution structure of a heparin dodecasaccharide composed solely of six GlcNS(6S)-IdoA(2S) repeat units has been determined using a combination of NMR spectroscopy and molecular modeling techniques. Two models were constructed, one in which all IdoA(2S) were in the 2S0 conformation (A and B below), and one in which they are in the 1C4 conformation (C and D below). However, no evidence suggests that changes between these conformations occur in a concerted fashion. These models correspond to the protein data bank code 1HPN.
Sources: en.wikipedia.org
Cool, dark, and dry conditions are standard, with storage at minus twenty degrees Celsius or below. Desiccant and sealed vials limit moisture uptake. Repeated warming and cooling of the container is generally avoided.
There is no single agreed limit, and laboratory practice varies widely. Refrigeration slows degradation, and freezing aliquots is often described for longer holding. Any visible cloudiness or precipitate indicates the solution should be discarded.
Mass spectrometry provides the most direct confirmation through molecular mass. Reversed-phase chromatography supports purity assessment, and peptide mapping or amino acid analysis can corroborate sequence. No single method establishes both purity and identity on its own.
No. It is a laboratory-synthesized analog built on a fragment of the natural hormone. The natural peptide is shorter-lived and lacks the stabilizing substitutions found in the synthetic version.