This is a working overview of DAC group, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-02-13. Anything still debated is marked as such rather than presented as settled.
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.
Stability depends heavily on physical state. A lyophilized powder kept dry, desiccated, and shielded from light typically holds its integrity for months to years at minus twenty degrees Celsius, and longer at minus eighty. Once dissolved, the peptide becomes far more vulnerable, since peptide bond hydrolysis, oxidation of susceptible residues, and aggregation all proceed faster in solution. Buffers near neutral pH are generally gentler than strongly acidic or alkaline conditions. Repeated freeze-thaw cycles and exposure to air-liquid interfaces during vigorous mixing cause losses that are easy to overlook.
Verification matters because research peptides vary widely in quality. A certificate of analysis is only as reliable as the method behind it, and a single chromatographic trace reveals little about counter-ions, residual solvents, or water content. Independent laboratories commonly pair mass confirmation with chromatographic purity and, where relevant, quantify water along with acetate or trifluoroacetate content. Reported purity figures are not standardized across suppliers, so a stated value such as ninety-eight percent is not directly comparable unless the analytical method, column, and detection wavelength accompany it.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | Analog of growth hormone-releasing hormone |
| Chain length | 29 amino acids | Based on the GRF(1-29) fragment |
| Appearance | White to off-white lyophilized powder | Common research supply form |
| Solubility | Soluble in water and aqueous buffers | Powder requires reconstitution before use |
| Typical storage | −20 °C or below | Kept away from light and moisture |
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.
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.
Purity is most often assessed by reversed-phase high-performance liquid chromatography, reported as a percentage of total peak area. Identity is confirmed by mass spectrometry, which yields a molecular ion consistent with the expected sequence. Amino acid analysis and peptide mapping provide additional characterization. Reported purity values are method-dependent, so figures from different laboratories are not always directly comparable without details of column, gradient, and detection wavelength.
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.
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.
Robert Graham Cooks is the Henry Bohn Hass Distinguished Professor of Chemistry in the Aston Laboratories for Mass Spectrometry at Purdue University. He is an ISI Highly Cited Chemist, with over 1,000 publications and an H-index of 150.
Sean Kinney said about the new album and the fans' mixed reactions about the band moving on after Staley's death: Look, it's a big move to fucking stand up and move on. Some people, the music connected with them so strongly, their opinions, how they feel about it ... It's amazing that they have such a connection but they seem to act like it happened to them. This happened to us and Layne's family, not them. This is actually our lives. If we're okay with it, why can't you be? This happened to us, this didn't happen to you. But this album isn't about that, it's a bigger universal point. We're all going to fucking die, we're all going to lose somebody, and it fucking hurts. How do you move on? This record is us moving on, and hurting. That, to me, is a victory. I already feel like I've won. Sometimes people ask us, 'Wouldn't Layne have been pissed off that we did this?' And I tell them it would have been the opposite: he would have been pissed off that it took us so long to do this. We're not doing this for money; there is no money in the music business anymore. Jerry and I funded the whole album, and we spent lots of our own money, because we believe in this. And one of the reasons I'm doing this is so more light is turned on to something where the light was turned off. And Cantrell added: "We've toured around the world, we've lost some friends, we buried a dear friend, and somebody that you just can't fucking replace, and then we've chosen by circumstance to get together again.
Upon hearing of the assassination of socialist candidate Jorge Eliécer Gaitán, many poor workers saw the death of Gaitán as a political assassination orchestrated by the rich. Workers began rioting and destroying the Colombian capital of Bogotá, leading to the death of 4,000 people. When news of the death of Gaitán reached the countryside, the local militias were furious and immediately started a civil war, known as La Violencia. Joined by fellow leftists, a brutal war was fought for over 10 years, leading to the death of 200,000 people and the destruction of much of the country, resulting in a peace settlement and the changing of power from the Colombian Conservative Party to the Colombian Liberal Party and the Colombian Communist Party in 1958. As La Violencia wound down, most self-defense and guerrilla units composed of Liberal Party supporters were demobilized. At the same time, some former liberals and active communist groups continued operating in several rural enclaves. One of the Liberal bands was a group known as the "Fuerzas Armadas Revolucionarias de Colombia" (Revolutionary Armed Forces of Colombia), or FARC, formed by Pedro Antonio Marín in 1964. The FARC was founded out of fighters who were unhappy with the peace settlement. The goal of the FARC, among other things, was land redistribution that would benefit poor peasant farmers like Marín, along with the desire to establish a socialist state. In 1958, an exclusively bipartisan political alternation system, known as the National Front, resulted from an agreement between the Liberal and Conservative parties.
Later in September Roche announced its intention to acquire Tusk Therapeutics for up to €655 million ($759 million) expanding Roche's oncology pipeline. Tusk announced that the anti-CD38 antibody it is developing will be spun off to form a new company, Black Belt Therapeutics. In late November, the company announced that Genentech would acquire Jecure Therapeutics, gaining access to Jecure's portfolio of NLRP3 inhibitors developed to fight inflammatory diseases like non-alcoholic steatohepatitis and liver fibrosis. In February 2019, the business announced it would acquire gene therapy company, Spark Therapeutics, for US$4.3 billion ($114.50 per share) adding Spark's gene therapy portfolio to its previous acquired assets. Spark has an already approved treatment for Leber's congenital amaurosis, Luxturna – priced at US$850,000 per patient. The offer to acquire Spark Therapeutics was extended to May 2019 after Roche was unable to garner majority support from Spark shareholders. A second gene therapy-related action came in December with the US$1.15 billion acquisition of non-United States rights to an investigational duchenne muscular dystrophy gene therapy developed by Sarepta Therapeutics. In November, Roche acquired Promedior and its lead treatment – PRM-151 – for the treatment of idiopathic pulmonary fibrosis, for $390 million upfront and another $1 billion in milestone payments.
Sources: en.wikipedia.org
In Japan, ivory carvings became popular in the 17th century during the Edo period, and many netsuke and kiseru, on which animals and legendary creatures were carved, and inro, on which ivory was inlaid, were made. From the mid-1800s, the new Meiji government's policy of promoting and exporting arts and crafts led to the frequent display of elaborate ivory crafts at World's fair. Among them, the best works were admired because they were purchased by Western museums, wealthy people, and the Japanese Imperial Family. The Buddhist cultures of Southeast Asia, including Myanmar, Thailand, Laos and Cambodia, traditionally harvested ivory from their domesticated elephants. Ivory was prized for containers due to its ability to keep an airtight seal. It was also commonly carved into elaborate seals utilized by officials to "sign" documents and decrees by stamping them with their unique official seal. In Southeast Asian countries, where Muslim Malay peoples live, such as Malaysia, Indonesia and the Philippines, ivory was the material of choice for making the handles of kris daggers. In the Philippines, ivory was also used to craft the faces and hands of Catholic icons and images of saints prevalent in the Santero culture. Tooth and tusk ivory can be carved into a vast variety of shapes and objects. Examples of modern carved ivory objects are okimono, netsukes, jewelry, flatware handles, furniture inlays, and piano keys.
=== Entry into bacteria === Penicillin can easily enter bacterial cells in the case of gram-positive species. This is because Gram-positive bacteria do not have an outer cell membrane and are simply enclosed in a thick cell wall. Penicillin molecules are small enough to pass through the spaces of glycoproteins in the cell wall. For this reason Gram-positive bacteria are very susceptible to penicillin (as first evidenced by the discovery of penicillin in 1928). Penicillin, or any other molecule, enters gram-negative bacteria in a different manner. The bacteria have thinner cell walls but the external surface is coated with an additional cell membrane, called the outer membrane. The outer membrane is a lipid layer (lipopolysaccharide chain) that blocks passage of water-soluble (hydrophilic) molecules like penicillin. It thus acts as the first line of defence against any toxic substance, which is the reason for relative resistance to antibiotics compared to gram-positive species. But penicillin can still enter gram-negative species by diffusing through aqueous channels called porins (outer membrane proteins), which are dispersed among the fatty molecules and can transport nutrients and antibiotics into the bacteria. Porins are large enough to allow diffusion of most penicillins, but the rate of diffusion through them is determined by the specific size of the drug molecules. For instance, penicillin G is large and enters through porins slowly; while smaller ampicillin and amoxicillin diffuse much faster.
=== Resale controversy === Under a resale arrangement, the Russian Direct Investment Fund (RDIF) offered Abu Dhabi-based firm, Aurugulf Health Investments the exclusive rights to sell the Sputnik V coronavirus vaccine. According to media reports, the vaccine was intended to be sold to a host of countries at huge premiums. As per documents reviewed by The Moscow Times, Emirati Sheikh Ahmed Dalmook al-Maktoum, a Dubai royal, worked as the middleman for reselling millions of Sputnik V vaccine doses to countries in dire need of COVID-19 vaccine at a higher premium. Corporate registry data showed that one of the two entities controlling Aurugulf is Royal Group, a conglomerate headed by UAE national security advisor, Sheikh Tahnoon bin Zayed al-Nahyan. Acquired documents, interviews with officials and buyer data showed that countries like Pakistan, Guyana, which were on the receiving end of the vaccine from the UAE, were coerced to pay more than double the price advertised by Russia. The same deal was further used for reselling 1 million Sputnik V vaccine doses by the Emirati royal Sheikh Ahmed Dalmook al-Maktoum to Kenya for huge mark-ups. However, the deal eventually failed as Nairobi learnt of the first shipment consisting of 75,000 doses not coming directly from Russia.
Sources: en.wikipedia.org
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.
DAC stands for drug affinity complex, a chemical group that binds the peptide to serum albumin. The binding slows clearance and lengthens the time the molecule stays in plasma compared with the unmodified analog.
Because two distinct molecules are discussed under one informal label. The albumin-binding version clears over several days, while the form without that group clears within roughly half an hour. Mixing results from both creates inconsistent figures.
Mass spectrometry establishes whether the observed molecular weight matches the calculated sequence mass. Chromatographic retention and fragment mapping add further confidence about sequence and composition. A single technique alone is rarely treated as sufficient evidence of identity.