DAC linker raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-11-25. Anything still debated is marked as such rather than presented as settled.
Clearance profiles diverge sharply between the two versions. The albumin-binding molecule stays in plasma for several days, whereas the unmodified analog is largely gone within about half an hour in reported work. Cleavage by dipeptidyl peptidase IV is a major contributor to the short life of the unmodified sequence. These gaps mean the two versions cannot be substituted for each other in study design or in reading results side by side.
Reports on this compound commonly follow serum growth hormone and insulin-like growth factor 1 across defined time windows. Protocols differ in sampling frequency, assay platform, and participant characteristics, which makes direct comparison between publications difficult. Some work focuses on pulsatile release patterns instead of average concentrations. Whether repeated exposure alters endogenous hormone rhythms over long periods remains an open question, and the formal literature is thinner than the volume of informal commentary implies.
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.
| Property | Value | Notes |
|---|---|---|
| Primary target | GHRH receptor | Present on pituitary somatotroph cells |
| Signal pathway | Gs, cyclic AMP, protein kinase A | Sequence follows receptor activation |
| Main measured effect | Growth hormone release | Insulin-like growth factor 1 shifts indirectly |
| Half-life, binding form | Several days | Extended through serum albumin association |
| Half-life, unmodified form | About 30 minutes | Limited mainly by enzymatic cleavage |
CJC-1295 belongs to a class of synthetic peptides modeled on growth hormone releasing hormone, a forty-four amino acid signal produced by the hypothalamus. The compound is built from the first twenty-nine residues of the natural sequence, with four substitutions introduced at positions 2, 8, 15 and 27. These changes were designed to slow enzymatic breakdown while preserving receptor activation. The result is a peptide that is shorter than native GHRH and considerably more resistant to ordinary clearance pathways in circulation.
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.
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.
== Prognosis == Fukuyama congenital muscular dystrophy has a poor prognosis. Most children with FCMD reach a maximum mobility at sitting upright and sliding. Due to the compounded effects of continually worsening heart problems, impaired mental development, problems swallowing and additional complications, children with FCMD rarely live through adolescence, the disorder proves fatal by age 20.
=== Purge gas === Purge gas is used to control the sample environment, in order to reduce signal noise and to prevent contamination. Mostly nitrogen is used and for temperatures above 600 °C, argon can be utilized to minimize heat loss due to the low thermal conductivity of argon. Air or pure oxygen can be used for oxidative tests like oxidative induction time and He is used for very low temperatures due to the low boiling temperature (~4.2K at 101.325 kPa ).
== Further reading == papuamide Ford, PW; Gustafson, KR; McKee, TC; Shigematsu, N; Maurizi, LK; Pannell, LK; Williams, DE; de Silva, ED; Lassota, P; Allen, TM; Van Soest, R; Andersen, RJ; Boyd, MR (1999). "Papuamides A-D, HIV-Inhibitory and Cytotoxic Depsipeptides from the Sponges Theonella mirabilis and Theonella swinhoei Collected in Papua New Guinea". J. Am. Chem. Soc. 121 (25): 5899–5909. Bibcode:1999JAChS.121.5899F. doi:10.1021/ja990582o. neamphamide A Oku, N; Gustafson, KR; Cartner, LK; Wilson, JA; Shigematsu, N; Hess, S; Pannell, LK; Boyd, MR; McMahon, JB (2004). "Neamphamide A. A new HIV-inhibitory depsipeptide from the Papua New Guinea marine sponge Neamphius huxleyi". J. Nat. Prod. 67 (8): 1407–11. Bibcode:2004JNAtP..67.1407O. doi:10.1021/np040003f. PMID 15332865. callipeltin A Zampella, A; D'Auria, MV; Paloma, LG; Casapullo, A; Minale, L; Debitus, C; Henin, Y (1996). "Callipeltin A, an Anti-HIV Cyclic Depsipeptide from the New Caledonian Lithistida Sponge Callipelta sp.". J. Am. Chem. Soc. 118 (26): 6202–9. Bibcode:1996JAChS.118.6202Z. doi:10.1021/ja954287p. mirabamides A-D Plaza, A; Gustchina, E; Baker, HL; Kelly, M; Bewley, CA (2007). "Mirabamides A-D. Depsipeptides from the sponge Siliquariaspongia mirabilis that inhibit HIV-1 fusion". J. Nat. Prod. 70 (11): 1753–60. Bibcode:2007JNAtP..70.1753P. doi:10.1021/np070306k. PMID 17963357.; Andjelic, CD; Planelles, V; Barrows, LR (2008). "Characterizing the Anti-HIV Activity of Papuamide A." Mar Drugs. 6 (4): 528–49. doi:10.3390/md20080027. PMC 2630844. PMID 19172193.
Sources: en.wikipedia.org
=== Skin === Deficiencies in vitamin A have been linked to an increased susceptibility to skin infection and inflammation. Vitamin A appears to modulate the innate immune response and maintains homeostasis of epithelial tissues and mucosa through its metabolite, retinoic acid (RA). As part of the innate immune system, toll-like receptors in skin cells respond to pathogens and cell damage by inducing a pro-inflammatory immune response which includes increased RA production. The epithelium of the skin encounters bacteria, fungi and viruses. Keratinocytes of the epidermal layer of the skin produce and secrete antimicrobial peptides (AMPs). Production of AMPs resistin and cathelicidin, are promoted by RA.
== Function == While most members of the POT family catalyze peptide transport, one is a nitrate permease and one can transport histidine, as well as peptides. Some of the peptide transporters can also transport antibiotics. They function by proton symport, but the substrate:H+ stoichiometry is variable: the high-affinity rat PepT2 carrier catalyzes uptake of 2 and 3 H+ with neutral and anionic dipeptides, respectively, while the low affinity PepT1 carrier catalyzes uptake of one H+ per neutral peptide.
Critics accused Mahathir of authoritarianism for centralising power and suppressing dissent, while supporters argued that his actions were necessary to preserve national stability. Mahathir resigned in 2003 after 22 years in office, but remained politically influential and was critical of his successors. He quit UMNO over the 1MDB corruption scandal in 2016, joining BERSATU and leading the Pakatan Harapan opposition coalition to victory in the 2018 general election. During a second tenure as prime minister, he pledged to investigate the 1MDB scandal, combat corruption, and cut spending on large infrastructure projects. He also secured the pardon and release of Anwar Ibrahim. Mahathir resigned in 2020 amidst a political crisis. Despite losing his parliamentary seat in the 2022 general election, he remained active in politics and shifted party affiliation several times. In 2019, Time magazine listed him as one of the world's 100 most influential people. Mahathir's political views have shifted during his life, and are shaped by his Malay nationalism and Islamic religious beliefs.
Sources: en.wikipedia.org
Many different inventions and ideas which may or may not have been practical about auto safety have been put forward but never made it to a production car. Such items include the driver seat in the middle (to give the person a better view) (the exception being the McLaren F1 super car) and control stick steering. Automotive safety may have become an issue almost from the beginning of mechanised road vehicle development. The second steam-powered "Fardier" (artillery tractor), created by Nicolas-Joseph Cugnot in 1771, is reported by some to have crashed into a wall during its demonstration run. However, according to Georges Ageon, the earliest mention of this occurrence dates from 1801 and it does not feature in contemporary accounts. One of the earliest recorded car-related fatalities was Mary Ward, on August 31, 1869, in Parsonstown, Ireland. In 1922, the Duesenburg Model A became the first car to have four-wheel hydraulic brakes.
Neutron capture reactions (n,γ), which are represented in the figure by a short right arrow. The (n,2n) reactions and the less frequently occurring (γ,n) reactions are also taken into account, both of which are marked by a short left arrow. Even more rarely and only triggered by fast neutrons, the (n,3n) reaction occurs, which is represented in the figure with one example, marked by a long left arrow. In addition to these neutron- or gamma-induced nuclear reactions, the radioactive conversion of actinide nuclides also affects the nuclide inventory in a reactor. These decay types are marked in the figure by diagonal arrows. The beta-minus decay, marked with an arrow pointing up-left, plays a major role for the balance of the particle densities of the nuclides. Nuclides decaying by positron emission (beta-plus decay) or electron capture (ϵ) do not occur in a nuclear reactor except as products of knockout reactions; their decays are marked with arrows pointing down-right. Due to the long half-lives of the given nuclides, alpha decay plays almost no role in the formation and decay of the actinides in a power reactor, as the residence time of the nuclear fuel in the reactor core is rather short (a few years). Exceptions are the two relatively short-lived nuclides 242Cm (T1/2 = 163 d) and 236Pu (T1/2 = 2.9 y). Only for these two cases, the α decay is marked on the nuclide map by a long arrow pointing down-left.
A 2015 systematic review and meta-analysis found that children with a family history of autoimmune diseases were at a greater risk of autism compared to children without such a history. When an underlying maternal autoimmune disease is present, antibodies circulating to the fetus could contribute to the development of autism spectrum disorders.
The team is commonly known as Los Cafeteros ("The Coffee Growers"), after Colombia's coffee industry, and as La Tricolor, after the yellow, blue and red of the national flag. The Colombian state broadcaster's archive service has described the shirt as having become "a new national symbol", worn across regions and social classes on match days. Colombia's yellow shirt, blue shorts and red socks are a relatively recent settlement rather than an inherited palette. Early sides alternated white and blue, with white worn at the 1945 South American Championship and dark blue at the 1962 FIFA World Cup. From 1971 the team wore orange, known domestically as zapote. In 1985 the Colombian Football Federation commissioned the designer María Elvira Pardo to base a kit on the national flag; her design made red the first-choice shirt, worn through the 1990 FIFA World Cup, with yellow as the alternative. Yellow was promoted to first choice in the early 1990s. Subsequent departures have been tournament-specific: a red change kit at the 2014 FIFA World Cup referencing the 1990s alternates, and a white first-choice shirt at the Copa América Centenario echoing the 1945 side. Adidas has supplied the team since January 2011 under an agreement signed in November 2010, subsequently extended to 2030; earlier suppliers included Le Coq Sportif, Adidas, Puma, Kelme, Umbro, Reebok and Lotto.
Sources: en.wikipedia.org
It acts on the growth hormone-releasing hormone receptor found on pituitary somatotroph cells. Activation of that receptor triggers growth hormone release through a cyclic AMP dependent pathway.
It links the peptide to serum albumin after administration, which delays removal from circulation. Reported half-life shifts from roughly half an hour to several days as a result.
Most published work tracks serum growth hormone and insulin-like growth factor 1 over time. Sampling schedules and assay methods vary enough that figures are not directly comparable across reports.
No. It is a laboratory-made analog of growth hormone-releasing hormone. The natural hormone is a 44-residue peptide, while the analog is built on a shorter 29-residue fragment.